用代入法解:4x-3y=36 3x+2y=78(要过程)用代入法解:4x-3y=363x+2y=78(要过程)

问题描述:

用代入法解:4x-3y=36 3x+2y=78(要过程)
用代入法解:4x-3y=36
3x+2y=78(要过程)

4x一3y=36,4x=36+3y,x=(36+3y)/4代入下式3(36+3y)/4+2y=78,(108+9y)/4+2y=78108+9y+8y=78X4,17y=312一108,y=204/17,y=12,代入上式,3x+2X12=78,3x=78一24,x=54/3,x=18