**a) $$(3a + 6)^2$$**
$$(3(a + 2))^2 = 3^2(a + 2)^2 = 9(a + 2)^2$$.
**в) $$(7x + 7y)^2$$**
$$(7(x + y))^2 = 7^2(x + y)^2 = 49(x + y)^2$$.
**г) $$(-3n + 6)^3$$**
$$(-3(n - 2))^3 = (-3)^3(n - 2)^3 = -27(n - 2)^3$$.
**д) $$(5q – 30)^3$$**
$$(5(q - 6))^3 = 5^3(q - 6)^3 = 125(q - 6)^3$$.
**е) $$(2a - 8)^4$$**
$$(2(a - 4))^4 = 2^4(a - 4)^4 = 16(a - 4)^4$$.