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

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Answer 1 · 2018-07-09T05:50:02

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

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 $(-3/2, 25/4)$

Answer 2 · 2018-07-09T12:06:48

$(3/2, 25/4)$

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

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

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

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

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