From the known condition that "A and B are reciprocal", then a+b=0, (the sum of two reciprocal numbers is zero), |a-5+b|=|(a+b)-5|=|0-5|=|-5|=5.

2) Answer

3) 1 1 or 1

M and n are reciprocal, then m+n = 0;

X and y are reciprocal, then x =1\ y;

If the absolute value of z is equal to 5, then |z|=5, that is, z=5 or z =-5;

2m+2n+6xy+z = 2 (m+n)+6 *1/y * y+z = 0+6 *1+z = 6+z, so when z=5, the answer is1/kloc-0.

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