Hi there!
To factor this expression, you must first find the greatest common factor of each term, 16x and 40y.
To do this, first list the factors of each coefficient since they do not share any variables:
16:1,2,4,8,16
40:1,2,4,5,8,10,20,40
Notice that among the factors of each term, 8 is the greatest common factor.
Finally, factor 8 from the expression to get 8(2x+5y) as your final answer.
Hope this helps, and have a nice day!
