Alg2 ch 4(1-4) Prac Test

This video is about Alg2 ch 4(1-4) Prac Test
#7 has a second solution (5x)^2 – (4y)^2
at 20:01 should be 9b^2, not 3b^2 which is fixed later at 22:28 for #9
The result should be 9b^3+108b^2+144b+64