Question

方程组x/2-y/3=2,2x+3y=28的解

Answer 1

(1) x/2-y/3=2①

2x+3y=28②

①两边乘以最小公倍数6 得3x-2y=12③

③-②得

x+5y=-16

x=-16+5y ④

把④代入③

3(-16+5y)-2y=12

-48+15y-2y=12

13y=12+48

y=60/13

把y=60/13代入④得

x=-16+5(60/13)

x=92/13

所以：x=92/13,y=60/13

(2) x/2-y/3=2

3x-2y=12① 6x-4y=24③

2x+3y=28② 6x+9y=84④

④-③得

13y=60

y=60/13

把y=60/13代入②

2x+180/13=28

2x=184/13

x=92/13

所以：x=92/13,y=60/13