Question

Subtract -2k3 + k2 - 9 from 5k3 - 3k + 7.

Answer 1

5k3 - 3k + 7 - (-2k3 + k2 - 9)
= 5k3 - 3k + 7 + 2k3 - k2 + 9
= 7k3 - k2 - 3k + 16

Answer 2

`7k^3-k^2-3k+16\\`

Explanation:

we have the expression:

`5k^3-3k+7`

and we must substract the other expression:

`-2k^3+k^2-9`

so we will get the following:

`5k^3-3k+7-(-2k^3+k^2-9)` (we put the minus sign because we are substracting)

So we solve this operation being carefull with the signs:

`5k^3-3k+7+2k^3-k^2+9\\`

and finally, joining like terms:

`7k^3-k^2-3k+16\\`