am i doing the setup right?

Question

Factor the polynomial completely.

2a²−6ab−20b²

sense 2 goes in both numbers wouldn't the setup be

2(a-5b) (a-2b) 

 

but i don't know what to do from here could someone please help me understand

Answer 1

2a² − 6ab − 20b²

 

As you noted, factor a 2 out:

 

2(a² - 3ab - 10b²)

 

Now factor the quadratic in the parentheses

 

2(a-5b)(a+2b)

 

The last factor is (a+2b), not (a-2b).  To check, multiply it back out to verify that you get 2a² − 6ab − 20b².  Otherwise you got it right, and it's fully factored.