ANSWER
3 must be factored from 3x² +9x
EXPLANATION
The given function is
[tex]y = 3 {x}^{2} + 9x - 18[/tex]
To write the given function in vertex form, we need to complete the square.
But before we come complete the square, we must ensure that the coefficient of the quadratic term is unity.
Hence we factor 3 from 3x² +9x to obtain:
[tex]y = 3( {x}^{2} + 3x) - 18[/tex]
The first choice is correct.
