Subtracting Polynomials

• April 8th 2012, 11:52 AM
batosaims
Subtracting Polynomials
2012-04-08144208.jpg picture by King_Bradley - Photobucket

You try 4

First thing I do is distribute the - to the second paranthesis so I get 3h^2-h+4

Then I do

-7h^2-8h+1
PLUS
3h^2-h+4

To get

-4h^2-9h+5

Wrong answer, I try subtracting

-7h^2-8h+1
minus
3h^2-h+4
______________
-10h^2-7h+5

What am I doing wrong?
• April 8th 2012, 01:07 PM
skeeter
Re: Subtracting Polynomials
$(7h^2 - 8h + 1) - (-3h^2 + h - 4) =$

note that the subtraction changes the sign of each term in the second trinomial ...

$7h^2 - 8h + 1 + 3h^2 - h + 4 =$

combine like terms ...

$10h^2 - 9h + 5$