◆◇◆(X-2Y)(3X-7Y)^2+4(Y-2X)(X+Y)^2 如何分解因式?还有 a^2+4b^2+9c^2-4ab-12b_数学解答

◆◇◆(X-2Y)(3X-7Y)^2+4(Y-2X)(X+Y)^2 如何分解因式?
还有 a^2+4b^2+9c^2-4ab-12bc+6ac
怎么分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分分

人气：244 ℃　时间：2019-10-19 06:25:46

解答

原式=（X-2Y）（3X-7Y+2X+2Y）（3X-7Y-2X-2Y）
=5（X-2Y）（X-Y）（X-9Y）