(1) 6#y=9,
即6y-5(6+y)=9
6y-30-5y=9
解得 y=39
(2)∵x#7=7x-5(x+7)=2x-35
∴7#(x#7)=7#(2x-35)=7
即 7(2x-35) -5(7+2x-35)=7
化简得4x=112,
解得 x=28
(1) 6#y=9,
即6y-5(6+y)=9
6y-30-5y=9
解得 y=39
(2)∵x#7=7x-5(x+7)=2x-35
∴7#(x#7)=7#(2x-35)=7
即 7(2x-35) -5(7+2x-35)=7
化简得4x=112,
解得 x=28