# What is the the vertex of y =4x^2-12x+9?

$x = \frac{- b}{2 a} = \frac{12}{8} = - \frac{3}{2}$
$y = y \left(- \frac{3}{2}\right) = 4 \left(\frac{9}{4}\right) - 12 \left(- \frac{3}{2}\right) + 9 = 9 + 18 + 9 = 36$