解二元一次方程组 x一y=200 (1+20%)x-(1-10%)y=780
2019-05-28
解二元一次方程组 x一y=200 (1+20%)x-(1-10%)y=780
优质解答
x一y=200
x=200+y
(1+20%)x-(1-10%)y=780
1.2x-0.9y=780
1.2*（200+y）-0.9y=780
240+1.2y-0.9y=780
0.3y=540
y=1800
x=2000
x一y=200
x=200+y
(1+20%)x-(1-10%)y=780
1.2x-0.9y=780
1.2*（200+y）-0.9y=780
240+1.2y-0.9y=780
0.3y=540
y=1800
x=2000