Question

m+2n分之2m-n的绝对值=3,求m+2n分之2(2m-n)-m+2n分之2m-n-3的值

Answer 1

∣(2m-n)/(m+2n)∣=3

(2m-n)/(m+2n)=±3

当(2m-n)/(m+2n)=3时

∣2(2m-n)/(m+2n)∣-(2m-n)/(m+2n)-3

=2∣(2m-n)/(m+2n)∣-(2m-n)/(m+2n)-3

=2*3-3-3

=0

当(2m-n)/(m+2n)=-3时

∣2(2m-n)/(m+2n)∣-(2m-n)/(m+2n)-3

=2∣(2m-n)/(m+2n)∣-(2m-n)/(m+2n)-3

=2*3-(-3)-3

=6+3-3

=6