3㎡-12m+12=0提公因数3得3(㎡-4m+4)=03(m-2)²=0M-2=0M=2
3㎡-12m+12=03(㎡-4m+4)=03(m-2)^2=0m-2=0m=2
(m-2)(3m-6)=0 m=2