Thread: subtracting polynomials

7x+1 - x^2+3x-8
i got x^2-4x+9 but my teacher said it was wronge. how do I correctly solve this problem?

Hello,

Where did the - go for x² ?

I am not sure why would the x^2 be negative i am so lost

Originally Posted by imbadatmath

I am not sure why would the x^2 be negative i am so lost

Are you subtracting the entire last 3 terms? If not, the original expression you entered was:



Grouping like terms and evaluating, we get:




Rearranging this into proper form, we get:



Does that make sense?

there where only 2 polnomials 7x+1 minus x^2+3x-8

Originally Posted by imbadatmath

there where only 2 polnomials 7x+1 minus x^2+3x-8

ok, then you should have written it like this:



Now, distribute the negative sign for the second polynomial:



Now group like terms:

thanks alot