Question

已知关于x,y的方程组{x+2y=3m,x-y=9m

Answer 1

x的值比y的值小5

y-x=5

x-y=-5

x-y=9m=-5

m=-5/9

x+2y=3m (1)

x-y=9m (2)

(1)*5+(2)*4

5(x+2y)+4(x-y)=5*3m+4*9m

9x+6y=51m

3x+2y=17m=17

m=1