Question

[x^3-(7x^2-x+1)]-[-x^3-(2x^2-x+7)]

Answer 1

I would do a bunch of distributing

Answer 2

-(2x^2-x+7)=?

Answer 3

just change all the signs inside the ( ) to opposite of what they were
and erase the - on the outside afterwards

Answer 4

you can do the same for -(7x^2-x+1)

Answer 5

i got 2x^3-5x^2+6

Answer 6

ok seems good then