To figure out the answer
First, you have to think what two number multiples that get -70 and when those same two numbers added get 3.
Well those two number would be 10 and -7
Set the up equation like this
x^2 -7x+10x-70
Next you would put parentheses to make this
(x^2-7x)+(10x-70)
Then you factor by taking out the common number and/or variables
So it will look like this
x(x-7) + 10(x-7)
So the answer is
(x+10) (x-7)