Let's factor this.
Factoring means we want something like
(x+_)(x+_)
Which numbers go in the blanks?
We need two numbers that...
Add together to get -7
Multiply together to get 10
Can you think of the two numbers?
Try -2 and -5:
-2+-5 = -7
-2*-5 = 10
Fill in the blanks in
(x+_)(x+_)
with -2 and -5 to get...
(x-2)(x-5)