3(a-b)²-7(a-b)+8(a-b)²+6(a-b),其中a-b=2.怎么写求解,

3(a-b)²-7(a-b)+8(a-b)²+6(a-b),其中a-b=2.怎么写求解,
3(a-b)²-7(a-b)+8(a-b)²+6(a-b),其中a-b=2.怎么写求解,

3(a-b)²-7(a-b)+8(a-b)²+6(a-b),其中a-b=2.怎么写求解,
3(a-b)²-7(a-b)+8(a-b)²+6(a-b),
=11(a-b)²-(a-b)
当a-b=2时原式=11*4-2=42

3(a-b)²-7(a-b)+8(a-b)²+6(a-b)，
=11﹙a－b﹚²－﹙a－b﹚
=11×2²－2
=42

分解因式最后得到11(a-b)²+6(a-b)
把a-b=2代进去最后等于56