现规定一种运算,a*b=ab+a-b,计算[5*(-7)]*(-2)
问题描述:
现规定一种运算,a*b=ab+a-b,计算[5*(-7)]*(-2)
答
∵a*b=ab+a-b,
∴5*(-7)
=5×(-7)+5-(-7)
=-35+5+7
=-23,
∴[5*(-7)]*(-2)
=(-23)*(-2)
=(-23)×(-2)+(-23)-(-2)
=46-23+2
=25.