Question

解方程组{4分之2x-3y+5分之2(x+2y)=1{4分之3(2x-3y)-5分之x+2y=-4

Answer 1

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

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

令 2x-3y =m x+2y = n 则：

m/4 +2n/5 = 1 ……①

3m/4 -n/5 = -4 ……②

①+②×2 得

7m/4 = -7

m= -4

n = 5

得新方程组：

2x- 3y =-4 ……③

x+2y = 5 ……④

④×2 - ③ 得

7y = 14

y = 2

x = 1