x-2y+z=1,2x+3y-z=2,求3x+8y-3z=?

问题描述:

x-2y+z=1,2x+3y-z=2,求3x+8y-3z=?

3
x-2y+z=1 ; (1)
2x+3y-z=2; (2)
(2)x2-(1)=3x+8y-3z=3能否再详细点(2)式x2:4x+6y-2z=4然后减去(1)式所以得到:3x+8y-3z=3