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Express y=x^2+x-12 in the form (x+a)^2-b

I've got

(x-2)^2-12

but not sure if correct?
Original post by Prefetch
I've got

(x-2)^2-12

but not sure if correct?


This is not quite right. If you expand out what you got, you get (x2−4x+4)−12(x^2-4x+4)-12

When we have something in the form x2+dx−ex^2+dx-e, we can write it in the form (x+a)2−b(x+a)^2-b by letting a=d2a=\frac{d}{2} and then −b=−(d2)2−e-b=-(\frac{d}{2})^2-e.

So can you follow this to get the right answer? :smile:
Reply 2
Avatar for Prefetch
Prefetch
OP
1
Thanks.

I think the answer is

(x+0.5)^2 - 12.25
Original post by Prefetch
Thanks.

I think the answer is

(x+0.5)^2 - 12.25


That's right!
Reply 4
Avatar for Mike173
Mike173
2
(x+0.5)^2 - 12.25

Complete the square!
Reply 5
Avatar for Prefetch
Prefetch
OP
1
Original post by Mike173
(x+0.5)^2 - 12.25

Complete the square!


Please clarify?
Reply 6
Avatar for Tau
Tau
10
Original post by Prefetch
Please clarify?


Completing the square is the process of converting an expression of the form cx2+dx+e cx^2 + dx + e into the form c(x+a)2−b c(x+a)^2 - b .
(edited 7 years ago)

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