# What is the vertex of y= 3x^2 + 9x − 4 ?

Mar 9, 2016

$V e r t e x \left(- \frac{3}{2} , - \frac{43}{4}\right)$

#### Explanation:

x-coordinate of vertex:
$x = - \frac{b}{2 a} = - \frac{9}{6} = - \frac{3}{2}$
y-coordinate of vertex:
$y \left(- \frac{2}{3}\right) = 3 \left(\frac{9}{4}\right) - 9 \left(\frac{3}{2}\right) - 4 = \frac{27}{4} - \frac{27}{2} - 4 =$
$= - \frac{27}{4} - 4 = - \frac{43}{4}$
$V e r t e x \left(- \frac{3}{2} , - \frac{43}{4}\right)$