990/x-990/(x+10%)=60/45 即[990(x+10%)-990x]/x(x+10%)=4/3 化简得:
1个回答

第一步[990(x+10%)-990x] =99

第二步 x(x+10%)= x^2 +1/10X

第三步99/x^2 +0.1X =4/3

4* x^2 +0.4X =3*99

4* x^2 +0.4X -297=0

再除以个 3 结果就是那么多了