Mathematics High School

Solve by completing the square : x^2+4x-7=0 and 2x^2+8x-1=0

Answers

Answer 1

By completing the squares we will see that the solutions are:

a) For 2x^2 + 8x - 1 = 0:

x = -2 ±√4.5

b) For x^2+4x-7 = 0

x = ±√11 - 2

How to complete squares?

Remember that the perfect square trinomial is:

(a + b)^2 = a^2 + 2ab + b^2

The first quadratic equation is:

2x^2 + 8x - 1 = 0

Dividing by 2 we get:

x^2 + 4x - 1/2 = 0

We can rewrite this as:

x^2 + 2*2*x - 1/2 = 0

Adding and subtracting 2^2 = 4, we get:

x^2 + 2*2*x + 4 - 4 - 1/2 = 0

(x + 2)^2 - 4 - 1/2 = 0

(x + 2)^2 = 4.5

Now we can solve this:

x + 2 = ±√4.5

x = -2 ±√4.5

These are the two solutions.

The other quadratic equation is:

x^2+4x-7 = 0

We can rewrite this as:

x^2 + 2*2*x - 7 = 0

Again, add and subtract 4 to get:

x^2 + 2*2*x + 4 - 4 - 7 = 0

(x + 2)^2 = 11

Solving this we get:

x = ±√11 - 2

Learn more about quadratic equations:

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Related Questions

A line has a slope of 0 and passes through the point (-4, 3). What is its equation in slope-intercept form.

Answers

Answer:

y = 3

Step-by-step explanation:

We already know the slope, all we need to do is find the y-intercept.

You have to plug the coordinates into the equation, y = 0x + b

y = 0x + b

3 = 0(-4) +b

3 = 0 + b

3 = b

The equation is y = 3

A construction crew is made up of 18 men; the rest are women. If 75% of
the crew are men, how many people are in the crew altogether?
24
22
28
20

Answers

Answer:

Step-by-step explanation:

I just took this test and got an A

Have a great day!

Answer:

Step-by-step explanation:

22 because I did it already

Jamie is twice as old as Natalie now. Give years ago the sum of their ages was 26. How old is each person now?

Answers

answer:

8. 67 and 17. 36

step-by-step explanation:

hi there!

to find out the age of both girls, i believe that we should divide the number 26 by 3 because jamie is twice as old as natalie meaning ( natalie ) is younger

26/3

= 8. 67

meaning 8.67 is how old natalie is/was

add 8.68 to itself once and you will get jamie's age!

8. 67 + 8. 67

= 17. 34

meaning 17. 34 is how old jamie is/was

sorry if i misread the question or made it a little confusing! but i do hope that this ends up helping you! :)

What is the length of bc in the right triangle below 9 12

Answers

Answer:

Step-by-step explanation:

hope it helps you.that was what I could think about.if am wrong please tell me.good day.

please help 15pts and will give brainlist!!

Answers

Answer:

1st ans

(x+15)=135(alternate angle)

x=135-15

x=120

2nd ans

(8x-4)=92(corresponding angle)

8x=92+4

x=96/8

x=12

3rd ans

(x+1)=51(vertically opposite angle)

x=51-1

x=50

Someone who can help me?

Answers

Answer:

4 days

Step-by-step explanation:

$0.09 × 100 = 9

$62.47 × 4 = 249.88

249.88 + 9 = 258.88

please help this is confusing me:(

Answers

Answer :
-8 miles per min
He travels 3.25min

-8 x 3.5= -26

He traveled 26 miles in 3.25

I hope this helped

Help please :)) Ignore the writing i was attempting to figure it out

Answers

Answer:

The answer is C. I hope this helps and is the paper red? That's cool. Anyways have a nice day!!

Step-by-step explanation:

Answer:

I think its is D but i'm not 100% sure

Shi ion even know loo

Answers

Answer:

1.6667

Step-by-step explanation:

1.6667
that was too easy

Samantha ordered lunch at a restaurant in the bill cost $64.21. she wants to leave a 15% tip. how much moeny would she leave for the tip amount

Answers

Answer:

9.6315

Step-by-step explanation:

Write the first six terms of f(n) = 4n-1

Answers

6
10
14
18 are the first six terms

Someone help and plz make sure it’s right

Answers

Answer:

Step-by-step explanation:

cosx=adjacent /h

What is the slope of the line RS that contains the points R(-2, -3), S(3, -5)
HELP ASAP

Answers

Answer:

[tex]slope = \dfrac{-2}{5}[/tex]

Step-by-step explanation:

The slope of a line passing through points , [tex] (x_1,y_1) [/tex] and [tex] (x_2,y_2) [/tex] is ,

[tex]\implies slope = \dfrac{y_2-y_1}{x_2-x_1}[/tex]

Using this we have ,

[tex]\implies slope = \dfrac{y_2-y_1}{x_2-x_1}\\\\\implies slope = \dfrac{-5+3}{3+2}\\\\\implies \boxed{\boxed{slope = \dfrac{-2}{5}}}[/tex]

Maria has 4 times as many necklaces as sheila toghter they have 25 necklaces how many necklaces does maria have

Answers

25/5=5 5*4=20 20+5=25.... Sheila has 5 necklaces while Maria has 20 necklaces

Drag the tiles to the correct boxes to complete the pairs. Not all tiles will be used.
Find the areas of the figures.
36 square units
54 square units
72 square units
190 square units

arrowRight

arrowRight

arrowRight

Answers

Answer:

The Answer to the first would be 36 i'm on the test myself and it makes sense for the 1st to be 54

the 2'd would be 72

the 3'rd would be 36

Step-by-step explanation:

A number cube is rolled what is the likelihood that a number less than or equal to three is rolled
Unlikely
Equally likely
Likely
Certain

Answers

Answer:

equally likely

Step-by-step explanation:

there are 3 numbers less than or equal to 3. divide that by every number on the cube. Then you get 0.5.

move the decimal twice and turn it into a percent 50%

50% is equally likely.

Find the surface area of the cone. Round your answer to the nearest tenth.

BRAIN>LY GIVING

Answers

Answer:

75.4

Step-by-step explanation:

Answer:

S.A = 65.94

Step-by-step explanation:

S.A = [tex]\pi r^{2} + \pi rl[/tex]

3.14 x 3 x 3 = 28.26

3.14 x 3 x 4 = 37.68

37.68 + 28.26 = 65.94

Let me know if this helps!

Charlie is saving for a new computer desk. The table costs $70. So far, she has already saved $35/ Write an equation to show how much more does she need to save to buy the desk. *Let x represent the amount of money that needs to be saved

Answers

Answer:

x + 35 = 70

-35 -35

–––––––––––

x = 35

Step-by-step explanation:

35 + 35 = 70

:))

.
Mary bought an antique vase to display her flowers like the one pictured below.

The vase has a radius of 1.5 inches and a height of 7 inches. If she wanted to wrap the vase for safe storage, which value best represents the total surface area?

65.97 inches square
14.14 inches square

80.11 inches square

10.5 inches square

Answers

for this i would use the equation of a cylinder to find the surface area and the equation would be 2(3.14)1.5(7) + 2(3.14)1.5 = 75.36 and you would want to wrap it in something bigger than the vase itself so the best answer would be 80.11 inches squared

Multiple Response. Select all the equations that have exactly one solution.

A. 3x + 1 = -3x + 7
B. 3x + 1 = x + 1
C. 3x + 1 = 3x + 7
D. 3x + 1 = 1/2 (1x + 1)
E. 3x + 3 = 3(x+1)

Answers

Answer:

A, B, D

Step-by-step explanation:

help me please??????

Answers

Answer:

I'm pretty sure it's D

if not then maybe B

A Baker uses the expression 5.75c + 3.45p to calculate his profit when he sells c cakes and p pies.

What is the bakers profit, in dollars, when he sells 33 cakes and 42 pies?

Answers

Answer:

334.65

Step-by-step explanation:

Multiply 5.75×33 and 3.45×42

then add them together to get 334.65

1 Well if the baker sells 33 cakes and each one is 5.75$ you just multiply the two to get : 189.75$2 Same goes for the pies if he sells 42 pies and each one is 3.45$ you just multiply the two to get: 144.90$

Do anyone know this problem?

Answers

Answer:

me kown it

Step-by-step explanation:

BRAINLIST‼️‼️WILL GIVE BRAILIDT

Answers

Answer:

Step-by-step explanation:

The fractuon 3/5 is found between which pair of fractions on a number line?

Answers

Answer: It's kinda simple, 2/5 and 4/5

Just add 1 to the numerator of the original fraction, and there's where you get 4/5. Then subtract 1 from the original fraction, and that's where you get 2/5!

How do I find tips and discounts?

Answers

Well, there are many apps and websites such as Honey to help you. You can also find then on newspapers and magazines where you can find coupons for discounts. And you can find tips in places like BRAINLY like I am doing now.

Can someone help me with this. Will Mark brainliest.

Answers

False hope that helps

Answer:

False

Step-by-step explanation:

because all four sides of a rectangle don't have to be equal. However, the sets of rectangles and rhombuses do intersect, and their intersection is the set of squares—all squares are both a rectangle and a rhombus.

:))

explain how finding the square root of a number is different from finding the cube root

Answers

U could searc9 it up and it will help u

PLEAS HELP ME WITH THIS EQUATION

For the equation y= 8 • 2x complete the table and plot the ordered pairs on the
graph.

Answers

Answer:

y=16x

Step-by-step explanation:

y=(8)(2)x

--HEART IF THIS HELPED OR BRAIN ME!!--

The ordered pairs (-3, 1), (-2, 2), (-1, 4), (0, 8), (1, 16), (2, 32) and (3, 64) on the graph are plotted below.

What is the exponential function?

Exponential function, as its name suggests, involves exponents. But note that, an exponential function has a constant as its base and a variable as its exponent but not the other way round (if a function has a variable as the base and a constant as the exponent then it is a power function but not an exponential function).

The given equation is y=8×2ˣ.

Here, in table

x -3 -2 -1 0 1 2 3

y 1 2 4 8 16 32 64

So, the ordered pairs are (-3, 1), (-2, 2), (-1, 4), (0, 8), (1, 16), (2, 32) and (3, 64)

Exponential functions have a horizontal asymptote. The equation of the horizontal asymptote is y=0.

Horizontal Asymptote: y=0

Therefore, the ordered pairs on the graph are plotted below.

Learn more about the exponential function here:

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I need help with this assignment please

Answers

i believe it would be option 3: center (-1,-5), radius: √41.

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