已知2x+3y+z=130,3x+5y+z=180,试求x+2y/x+y+z的值
问题描述:
已知2x+3y+z=130,3x+5y+z=180,试求x+2y/x+y+z的值
答
2x+3y+z=130
4x+6y+2z =260
用4x+6y+2z =260 减去 3x+5y+z=180得到:
(4x+6y+2z )- (3x+5y+z)=260-180
x+y+z =80
用3x+5y+z=180 减去 2x+3y+z=130 得到:
x+2y =50
所以:x+2y/x+y+z =50/80 =5/8