Question

g(x) = 3x2 + 12x + 15 Put it in vertex form

Answer 1

-12/ 2*15*3

Answer 2

-2/15

Answer 3

well start by writing it as

\[y = 3(x^2 + 4x) + 15\]

complete the square on the terms inside the brackets.... what would you add for a perfect square?

Answer 4

16???

Answer 5

not quite you add half of the coefficient of the term in x, and square it

so

(4/2)^2 = ?

Answer 6

4

Answer 7

yes... so the equation is

\[y = 3(x^2 + 4x + 4) + 15 - 3\times 4\]

you just add 4 inside the brackets so to kee the equation in balance you need to subtract 3 lots of 4... so the equation is

\[y = 3(x^2 + 4x + 4) + 3\]

now just factor the quadratic, which is a perfect square to get the vertex form

Answer 8

im still confused