Question

三元一次方程组：z=x+y,2x-3y+2z=5,x+2y-z=3

Answer 1

z=x+y.(1)

2x-3y+2z=5.(2)

x+2y-z=3.(3)

把(1)代入(2)(3)得

4x-y=5.(4)

y=3.(5)

把(5)代入(4)得

4x-3=5

x=2

由(1)

z=x+y=5

解得

x=2

y=3

z=5