Question

5а- ab + 5с- сb. 4. 9а2 - с2

Answer 1

5a - ab + 5c - cb = (5a - ab) + (5c - cb) = a(5 - b) + c(5 - b) = (5 - b)(a + c)

9a² - c² = (3a)² - c² = (3a - c)(3a + c)