Let's factor all four of these before we multiply.
x² - 25
We want two numbers that add to -25 and multiply to 0.
= (x+5)(x-5)
x² - 2x
Both terms are divisible by x.
= x(x-2)
x - 2
unfactorable
x² + 5x
Both terms are divisible by x.
= x(x+5)
Now we have this:
Let's go ahead and multiply across.
Cancel out the (x+5) and (x-2) from the top and the bottom.