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

3rd one

Step-by-step explanation: I am pretty sure becuase the other ones don't sound right hope this helps :)

Answer 2

(a) 3 must be factored from 3x^2 + 9x

Explanation:

The first step when rewriting a quadratic from standard form to vertex form is to factor out the leading coefficient from the variable terms.

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y = 3x^2 +9x -18 . . . . . . given

y = 3(x^2 +3x) -18 . . . . . leading coefficient factored out

y = 3(x^2 +3x +2.25) -18 -3(2.25) . . . . . complete the square

y = 3(x +1.5)^2 -24.75 . . . . . simplify to vertex form