Разложите на множители: 1) 18xy - 6x²; 2) 15a⁶ - 3a⁴; 3) 4x - 4y + cx - cy.

1) 18xy - 6x² = 6x(3y - x) 2) 15a⁶ - 3a⁴ = 3a⁴(5a² - 1) 3) 4x - 4y + cx - cy = 4(x - y) + c(x - y) = (x - y)(4 + c)