The question requires you to subtract 10x^2 - 10x + 2 from -8x^2 + 7x - 7
That is, -8x^2 + 7x - 7 - (10x^2 -10x + 2)
Note that when solving for addition and subtraction of binomials and polynomials, the important thing to look out for is the index power of each unknown variable. In other words, a variable that is raised to the power of 2 cannot be added to or subtracted from another variable raised to to the power of 1. Hence, x^2 cannot be added to or subtracted from x (or x^3) and so on.
Therfore both expressions having being written out can now be simplified, and note here that the minus sign between both expressions is significant. The minus sign affects every expression inside the parenthesis on the right side.
-8x^2 + 7x - 7 - 10x^2 + 10x - 2
(Please remeber that minus times minus is positive, and minus times plus is negative)
We can now re-arrange the expressions according to like terms as follows;
-8x^2 - 10x^2 + 7x + 10x - 7 - 2
-18x^2 +17x -9