对于有理数,定义一种运算“()”使a()b=3a+b/a-3b,求(-2)()[7()(-6)]的值.

问题描述:

对于有理数,定义一种运算“()”使a()b=3a+b/a-3b,求(-2)()[7()(-6)]的值.

(-2)()[7()(-6)]
=(-2)()[3*7+(-6)/7-3*(-6)]
=(-2)()[21+(-6/7)+18]
=(-2)()[39-(6/7)]
=(-2)()(267/7)
=3*(-2)+267/7/(-2)-3*267/7
=(-6)-267/14-801/7
=(-84/14)-267/14-1602/14
=-(84+267+1602)/14
=139.5

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