(X-10)(X-10)
You need to first multiply out the brackets. So, first times X by X, which makes x^2 . Then do -10 x -10 which makes 100. You then need to multiply the X within the first bracket with the minus 10 in the second bracket which makes -10x. Do the same but with the -10 from the first bracket and the X from the second which again makes -10x. So altogether you have x^2-10x-10x+100. This can be simplified down to x^2-20x+100. You then do the same thing for the second question :)
