(2a-3b)(2a+3b) = 4a^2 - 9b^2
42a^5 - 6a^4 + 30a^3 = 6a^3(7a^2 - a + 5)
8ab - 14a - 12b + 21 = (2b - 3)(4a - 7)
x^2 - 5x - 9xy + 45y = (x - 9y)(x + y)
(2a-3b)(2a+3b) = 4a^2 - 9b^2
42a^5 - 6a^4 + 30a^3 = 6a^3(7a^2 - a + 5)
8ab - 14a - 12b + 21 = (2b - 3)(4a - 7)
x^2 - 5x - 9xy + 45y = (x - 9y)(x + y)