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The function p(x) = –8x2 – 64x can be written in vertex form p(x) = a(x – h)2 + k, where a =

User Penni
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means compplete the square on one side

basically get into form
f(x)=a(x-h)^2+k


ok, group x terms

p(x)=(-8x^2-64x)
factor out linear coefient (-8)

p(x)=-8(x^2+8x)
take 1/2 of the linear coefient and square it
8/2=4, 4^2=16
add positive and negaitve of that inside parntheaese

p(x)=-8(x^2+8x+16-16)
factor perfect square

p(x)=-8((x+4)^2-16)
expand

p(x)=-8(x+4)^2+128

in vertex form it is
p(x)=-8(x+4)^2+128
User Tmandry
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