Question

What is the first step when rewriting y = 3x2 + 9x – 18 in the form y = a(x – h)2 + k? 3 must be factored from 3x2 + 9x x must be factored from 3x2 + 9x 9 must be factored from 9x – 18 3 must be factored from 3x2 – 18

Answer 1

3 must be factored from 3x²+9x:
3(x²+3x)-18

Answer 2

A. 3 must be factored from
`3x^2+9x`.

Explanation:

We have been given an equation
`y=3x^2+9x-18`. We are asked to choose the correct step, which will convert our given equation in form
`a(x-h)^2+k`.

To find the vertex of parabola we use formula
`(-b)/(2a)`, where b represents coefficient of x and a represents coefficient of
`x^2`.

So we can convert our given equation in vertex form of parabola by factoring out greatest common factor of first two terms of our given equation as:

`3(x^2+3x)`

Therefore, option A is the correct choice.