Question

关于x、y的二元一次方程组{2x+3y=m+1,3x-y=2m-3,的解满足x+y=0,试求m的值

Answer 1

2x+3y=m+1 (1)

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

(1)x3+(2)

9x+3x=3m+3+2m-3

12x=5m

x=5m/12

(1)x3-(2)x2

9y+2y=3m+3-4m+6

11y=9-m

y=(9-m)/11

x+y=0

5m/12+(9-m)/11=0

55m+108-12=0

43m=-108

m=-108/43