规定一种运算 a*b=ab+a-b,求(-4)*[(-5)*(-6)]?

问题描述:

规定一种运算 a*b=ab+a-b,求(-4)*[(-5)*(-6)]?

(-4)*[(-5)*(-6)]
=(-4)*[(-5)(-6)+(-5)-(-6)]
=(-4)*[30-5+6]
=(-4)*31
=(-4)(+31)+(-4)-(+31)
=-124-4-31
=-159

(-5)*(-6)
=(-5)×(-6)+(-5)-(-6)
=30-5+6
=31
(-4)*[(-5)*(-6)]
=(-4)*31
=-4×31+(-4)-31
=-124-4-31
=-159