how to combine like terms? make it equal to zero..easy question?

it doesn't matter which side you go to and you don't get different answers

-x + 11 = x^2 - 11x

-x^2 + 10x + 11 = 0

-(x^2 - 10x - 11) = 0

x^2 - 10x - 11 = 0/-1

x^2 - 10x - 11 = 0

(x + 1)(x - 11) = 0

x = -1, 11

..........................

-x + 11 = x^2 - 11x

0 = x^2 - 10x - 11

0 = (x + 1)(x - 11)

x = -1, 11

Since you have an x², you want to solve this as a quadratic & hopefully be able to factor it. So you need to get it into this form

ax² + bx + c = 0

or the easy way to think about it is to move every thing to the left.

-x + 11 = x² - 11x

I'm going to flip sides to get a positive x² on the left

x² - 11x = -x + 11

Now I'm going to add x - 11 to both sides

x² - 11x + x - 11 = -x + 11 + x - 11

x² - 10x - 11 = 0

Now to see if it can be factored

(x - 11)(x + 1) = 0, yep, it can be factored

For that to be true, x = 11 or -1, that should be the answer you have

place all the same terms on the same side remembering to change the signs when crossing the equal sign. And then combine the terms.

Example: - x + 11 = x^2 - 11x then it's - x + 11x = x^2 - 11, then combine. 10x = x^2 - 11.