Question

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

Answer 1

Vertex is at `(1.25 , -12.25)`

Explanation:

`y=(x-3)(4 x+2) or y= 4 x^2 -10 x -6`

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

Vertex ( x coordinate) is `v_x= (-b)/(2 a)=10/8=1.25`

Putting `x=1.25` in the equation we get `v_y`

Vertex ( y coordinate) is

`v_y= 4 *1.25^2-10 *1.25-6=-12.25`

Vertex is at `(1.25, -12.25)`

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