已知4-x+2y=0求10+6y-3x的值

问题描述:

已知4-x+2y=0求10+6y-3x的值

10+6y-3x
=10+3(2y-x)
=10+3(2y-x-0)
=10+3(2y-x-4+x-2y)
=-2

由 4-x+2y=0 得 x-2y=4
所以 10+6y-3x=10-3(x-2y)=10-12=-2

10+6y-3x
=6y-3x+10
=3(2y-x)+10
因为4-x+2y=0
2y-x=4
所以
3(2y-x)+10
=3*4+10
=12+10
=22

4-x+2y=0
2y-x=-4
10+6y-3x
=10+3(2y-x)
=10+3*(-4)
=-2