4. Упростите выражение: 1) a) $$3(2a-5b)^2-12(a-b)^2$$; 2) a) $$(3x^2+4)^2+(3x^2-4)^2-2(5-3x^2)(5+3x^2)$$; 3) a) $$(p-2a)(p+2a)-(p-a)(p^2+pa+a^2)$$; 6) $$7(2a+5)^2+5(2a-7)^2$$; 6) $$(4a^3+5)^2+(4a^3-1)^2-2(4a^3+5)(4a^3-1)$$; 6) $$x(2x-1)^2-2(x^2+1)(x-1)^2$$.

1) a) $$3(2a-5b)^2-12(a-b)^2 = 3(4a^2 - 20ab + 25b^2) - 12(a^2 - 2ab + b^2) = 12a^2 - 60ab + 75b^2 - 12a^2 + 24ab - 12b^2 = -36ab + 63b^2 = 9b(-4a + 7b)$$ б) $$7(2a+5)^2 + 5(2a-7)^2 = 7(4a^2 + 20a + 25) + 5(4a^2 - 28a + 49) = 28a^2 + 140a + 175 + 20a^2 - 140a + 245 = 48a^2 + 420$$ 2) a) $$(3x^2+4)^2+(3x^2-4)^2-2(5-3x^2)(5+3x^2) = (9x^4 + 24x^2 + 16) + (9x^4 - 24x^2 + 16) - 2(25 - 9x^4) = 18x^4 + 32 - 50 + 18x^4 = 36x^4 - 18$$ б) $$(4a^3+5)^2+(4a^3-1)^2-2(4a^3+5)(4a^3-1) = (16a^6 + 40a^3 + 25) + (16a^6 - 8a^3 + 1) - 2(16a^6 + 20a^3 - 4a^3 - 5) = 32a^6 + 32a^3 + 26 - 32a^6 - 32a^3 + 10 = 36$$ 3) a) $$(p-2a)(p+2a)-(p-a)(p^2+pa+a^2) = (p^2 - 4a^2) - (p^3 - a^3) = p^2 - 4a^2 - p^3 + a^3$$ б) $$x(2x-1)^2-2(x^2+1)(x-1)^2 = x(4x^2 - 4x + 1) - 2(x^2 + 1)(x^2 - 2x + 1) = 4x^3 - 4x^2 + x - 2(x^4 - 2x^3 + x^2 + x^2 - 2x + 1) = 4x^3 - 4x^2 + x - 2(x^4 - 2x^3 + 2x^2 - 2x + 1) = 4x^3 - 4x^2 + x - 2x^4 + 4x^3 - 4x^2 + 4x - 2 = -2x^4 + 8x^3 - 8x^2 + 5x - 2$$