解二元一次方程2分之X+Y加三分之X—Y等于6 4(X+Y)—3(X—Y)=--20

问题描述:

解二元一次方程2分之X+Y加三分之X—Y等于6 4(X+Y)—3(X—Y)=--20

题目是这样的:(X+Y)/2+(X-Y)/3=6 (1)4(X+Y)-3(X-Y)=-20 (2)将(1)两边同时乘以6得 3X+3Y+2X-2Y=36 →5X+Y=36 (3)将(2)化解为4X+4Y-3X+3Y=-20 →X+7Y=-20 (4)将(4)乘以5得5X+35Y=-100 (5)(5)-(3)得...