# What is the vertex of the parabola #y= -2(x+3)(x-1)#?

##### 1 Answer

Apr 27, 2018

#### Explanation:

#"the vertex lies on the axis of symmetry which is situated"#

#"at the midpoint of the zeros"#

#" to find zeros let y = 0"#

#rArr-2(x+3)(x-1)=0#

#"equate each factor to zero and solve for x"#

#x-1=0rArrx=1#

#x+3=0rArrx=-3#

#"axis of symmetry is "x=(1-3)/2=-1#

#"x-coordinate of vertex "=-1#

#"substitute "x=-1" into the equation for y-coordinate"#

#rArry=-2(2)(-2)=8#

#rArrcolor(magenta)"vertex "=(-1,8)#

graph{(y+2x^2+4x-6)((x+1)^2+(y-8)^2-0.04)=0 [-20, 20, -10, 10]}