Complete the square to write y = 3x^2 + 12x + 7 in vertex form, y = a(x - h)^2 + k. y = 3(x^2 + 4x) + 7
y = 3(x^2 + 4x + 4) + 7 -

When the above expression is written in vertex form, a is [-5 , -2, or 3], h is [-5, -2, or 3], and k is [-5, -2, or 3].