3m^2n-12mn+12n

因式分解 3m^2n-12mn+12n 3m^2n-12mn+12n m+n=3 mn=-2 求5m-3mn-7n+12mn-7m+5n的值 急~~~ m^2-mn=20,mn-n^2=-12 m^2-n与-2mn+n^2 3m的平方n-12mn+12n 已知实数m,n,且m>n>0,m²+n²=4mn,则m²﹣n²/mn的值等于∵(m+n)²=m²+2mn+n²,(m-n)²=m²-2mn+n²,m²+n²=4mn.(m+n)²=6mn(m-n)²=2mn(m+n)²(m-n)²=12m²n²mm³-2m
-3m^2+9mn+12n^2十字相乘 m=-4,n=-12,求(m+n)(m^2-mn+n^2)的值 分解因式：－4m^2n^3+12m^3n^2-2mn 已知m^2-mn=20,mn-n^2=-12,求代数式m^2-n^3的值 m^3+6m^2n+12mn^2+8n^3-27 因式分解 已知m+n=12 ,mn=3,那么m^2-mn+n^2=?我算135 已知m^2+n^2=3,mn=-1,求多项式5m^2-3mn+12mn-7m^2+5n^2的值. 1/M+1/N=5 (3M+MN+2N) / (M-MN=3N) 2mn[（2mn）^2-3n（mn+m^2*n）-mn^2]计算 2mn[(2mn)²-3n（mn+m²n）-mn² 3m^2 n^2+12mn+12+x(mn+2)^2 3m^2n^2+12mn+x(mn+2)^2因式分解.同上.