Question

解三元一次方程：｛4x+2y+z=5,4x-2y+z=1,z=-1

Answer 1

方程组

4x + 2y + z = 5

4x - 2y + z = 1

z = -1

那么,

4x + 2y - 1 = 5

4x + 2y = 6

2x + y = 3

另一个

4x - 2y - 1 = 1

4x - 2y = 2

2x - y = 1

两式相加消元

4x = 4

x = 1

这样

2 + y = 3

y = 1

方程组是

x = 1 ,

y = 1 ,

z = -1