The Student Room Group

Completing the Square

x2+2x-7=(x+a)2+b
if a = 1 then b=?
x^2 2x-7
(x^2 2x 1)-1-7
(x 1)^2-8
so a=1, b=8
(edited 5 years ago)
Reply 2
Original post by ctkching
x^2 2x-7
(x^2 2x 1)-1-7
(x 1)^2-8
so a=1, b=-8

the answer is -8 actually

but still thanks!!!

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