已知有理数a,b满足|a+1/2|+|b-1/2|=0求(3/a-7*b)/(a*b)的值

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已知有理数a,b满足|a+1/2|+|b-1/2|=0求(3/a-7*b)/(a*b)的值
已知有理数a,b满足|a+1/2|+|b-1/2|=0求(3/a-7*b)/(a*b)的值

已知有理数a,b满足|a+1/2|+|b-1/2|=0求(3/a-7*b)/(a*b)的值
∵|a+1/2|+|b-1/2|=0
∴a=-1/2 b=1/2
∴(3/a-7*b)/(a*b)
=[3/(-1/2)-7*1/2]/(-1/2*1/2)
=(-6-7/2)/(-1/4)
=(-19/2)/(-1/4)
=38

因为|a+1/2|+|b-1/2|=0
所以a+1/2=0 b-1/2=0
a= -1/2 b= 1/2
则(3/a-7*b)/(a*b)
=【3÷(-1/2)-7×1/2】÷(-1/2×1/2)
=【-6-3.5】÷(-1/4)
= -9.5×(-4)
=38

a+1/2=0,a=-1/2
b-1/2=0,b=1/2
(3/a-7*b)/(a*b)
=(-6-7/2)/(-1/4)
=24+14
=38

a=-1/2 b=1/2
解得原式=(-6-7/2)/(-1/4) = -19/2 * -4 = 38

a+1/2=0, b-1/2=0
a=-1/2, b=1/2
(3/a-7*b)/(a*b)=(-6-7/2)/(-1/2*1/2)=38