Write the expression 5x (x + 9) - 7 (x + 9) in complete factored form

Remember the distributive property

a (b+c) = ab+ac

reverse it

ab+ac=a (b+c)

5x (x+9) - 7 (x+9)

notice that (x+9) is common to both, just like a

(5x-7) (x+9)

So the problem ask to complete the factored form in the equation but first of the you must keep in mind that the common of the two is (x+9), so it means that you can rewrite the equation in to a simplest form and that would be (x+9) (5x-7). I hope you are satisfied with my answer and feel free to ask for more