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Help on polynomial c1 question

The question is:
Express in the form a(x+b)^2+c
2x^2-8x-7
The answers on the next page says
=2[x^2-4x]-7
=2[(X-2)^2-4]-7
=2(X-2)^2-15

I get it all to the last bit how does it go from the second step to having -15


Posted from TSR Mobile
Hey look a question I can answer ^_^ (i think). You multiply the 2 by the -four as the -four is in the square bracket. 2*-4 =-8. Then -8-7 = -15
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lkjhgfdsasd
OP
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Original post by brandonofcourse
Hey look a question I can answer ^_^ (i think). You multiply the 2 by the -four as the -four is in the square bracket. 2*-4 =-8. Then -8-7 = -15


Omg that looks so obvious now, thanks!!


Posted from TSR Mobile
Capture.JPG

Just clearing this up for any future viewers who are really stuck. (see attached)
Reply 4
Avatar for lkjhgfdsasd
lkjhgfdsasd
OP
2
Original post by PedanticStudent
Capture.JPG

Just clearing this up for any future viewers who are really stuck. (see attached)


This is such a good explanation


Posted from TSR Mobile
Reply 5
Avatar for RValue
RValue
Original post by PedanticStudent
Capture.JPG

Just clearing this up for any future viewers who are really stuck. (see attached)


ur alrite m8
k

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