5. (x + 6y?)(x - 6y
6. (3x2 - 11)(3x2 + 11)
7. (4xy + 3z)(4xy - 3z?)
8. (3x3 - 4)(3x3 + 4)
9. (x + 4y) [(x - 4y)
10.(2x - 3y)(2x + 3y)​