Question

Is 2(x-4)^2-19 the vertex form of 2x^2+8x-3?

Answer 1

expand 2(x - 4)^2 -19 and see what you get

Answer 2

I see now that it is incorrect. Do you think you could help me with finding the vertex from of 2x^2+8x-3? @welshfella

Answer 3

ok first divide the first divide first 2 terms in the equation by 2:-

2 [x^2 + 4x ] - 3
Now rewrite the term in the brackets
2[ (x + 2)^2 - 4] - 3

= 2(x + 2)^2 -8 - 3
= 2(x + 2)^2 - 11

Answer 4

I follow with the first line of number but the second one I'm confused with

Answer 5

to rewrite (x^2 + 4 ) you use the identity

a^2 + bx = (a + b/2)^2 - (b/2)^2

Answer 6

* rewrite (x^2 + 4x) I should have said

Answer 7

if you expand (x + 2)^2 you get x^2 + 4x + 4 right?
now if we subtarct 4 we get back to x^2 + 4x

x^2 + 4x + 4 - 4 = x^2 + 4x


its another way of writing x^2 + 4x

Answer 8

I didn't know at first that if you expand (x + 2)^2 you get x^2 + 4x + 4. but i get it now.

Answer 9

(x + 2)(x+2) = x(x + 2) + 2(x + 2)

Answer 10

I get it now wow.

Answer 11

good