商是除数的3倍,被除数,除数,商的和是120,问商、除数、被除数各是多少?

问题描述:

商是除数的3倍,被除数,除数,商的和是120,问商、除数、被除数各是多少?

被除数x 除数y
(x-2)/3y=3 => x-2=9y =>x=9y+2
(11x-9)/y=78 => 11x-9=78y
有上述推的 => 11(9y+2)-9=78y => 99y+22-9-78y=0 => 21y=-13 =>y=-13/21 x=-25/7