# What is the vertex of y= (x − 3)(4x + 2) ?

Jun 17, 2018

Vertex is at $\left(1.25 , - 12.25\right)$

#### Explanation:

$y = \left(x - 3\right) \left(4 x + 2\right) \mathmr{and} y = 4 {x}^{2} - 10 x - 6$

 a= 4 , b= -10 ,c =-6 ; [y= ax^2+bx+c

Vertex ( x coordinate) is ${v}_{x} = \frac{- b}{2 a} = \frac{10}{8} = 1.25$

Putting $x = 1.25$ in the equation we get ${v}_{y}$

Vertex ( y coordinate) is

${v}_{y} = 4 \cdot {1.25}^{2} - 10 \cdot 1.25 - 6 = - 12.25$

Vertex is at $\left(1.25 , - 12.25\right)$

graph{y=(x-3)(4x+2) [-40, 40, -20, 20]} [Ans]