Find the vertex of y=-(x-1)(x+4)?

2 Answers
Jul 9, 2018

Vertex #(-3/2, 25/4)#

Explanation:

Given -

#y=-(x-1)(x+4)#

#y=-(x^2-x+4x-4)#

#y=-(x^2+3x-4)#

#y=-x^2-3x+4#

#x=(-b)/(2a)=(-(-3))/(2 xx -1)=3/(-2)=-3/2#

At #x=-3/2; y=-(-3/2)^2-3(-3/2)+4#

#y=-9/4+9/2+4=(-9+18+16)/4=25/4#

Vertex #(-3/2, 25/4)#

Jul 9, 2018

#(3/2, 25/4)#

Explanation:

#y=-(x-1)*(x+4)#

#y=-x^2-3x+4#

#y=-x^2-3x-(3/2)^2+4+(3/2)^2#

#y=25/4-(x-3/2)^2#

Hence vertex of this equation is #(3/2, 25/4)#