Question

How do you find the vertex form of f(x)=-2x^2-6x+10

Answer 1

Completing the square! Go!

Answer 2

thats what im trying to do but I dont understand how

Answer 3

Two hints.

1) Think long and hard on this: \((a+b)^{2} = a^{2} + 2ab + b^{2}\)

2) f(x)=-2x^2 - 6x + 10 = -2(x^2 + 3x + ______) + 10 - (-2)(______)

Just fill in that big blank with the same value. What is the value? Please see hint number 1).

Answer 4

give me a sec

Answer 5

still not really fully understanding

Answer 6

Hint #3) You have 2b and you need b^2. Give it another go.

Answer 7

I'm sorry no im not getting the second number that is needed.

Answer 8

i got -2(x-__)^2

Answer 9

One more.

2b = 3

Find b^2

Answer 10

2.25

Answer 11

sorry for taking so much of your time

Answer 12

Don't use 2.25. Stick with fractions.

b = 3/2

b^2 = 9/4

f(x)=-2x^2 - 6x + 10 = -2(x^2 + 3x + 9/4) + 10 - (-2)(9/4)

Can you simplify that right-hand expression?

Answer 13

didnt notice the message earlier i sticked with the decimal and got -2(x^2+1.5)+14.5

Answer 14

@tkhunny

Answer 15

-2(X+9/4) + 7

Answer 16

(x^2 + 3x + 9/4) = (x + 3/2)^2

10 + (2)(9/4) = 10 + 9/2 = 20/2 + 9/2 = 29/2

Work on your algebra. You'll get it.