Answer:
15a^2 -17a +4
5a x 3a = 15a^2 bc a times a makes it squared.
next, 5a x -1 = -5a
and then -4 x 3a = -12a
-5a -12a (bc they're like terms) = -17a
then, -4 x -1= 4 ( two negs cancel each other out)
I apologize for my mistake the first time
