2x-3y/4+2(x+2y)/5=1 3(2x-3y)/4-x+2y/4=0

(1)2x-3y/4+2(x+2y)/5=1
方程两边同时乘以20得
40x-15y+8（x+2y）=20
40x-15y+8x+16y=20
48x+y=20
y=20-48x
(2) 3(2x-3y)/4-x+2y/4=0
方程两边同时乘以4得
3（2x-3y）-4x+2y=0
6x-9y-4x+2y=0
2x-7y=0
把（1）带入（2）得
2x-7（20-48x）=0
解得：x=70/169,y=20/169