若X比Y比Z=3比4比7,且2X-Y+Z=18那么X+2Y+3Z的值是多少?
问题描述:
若X比Y比Z=3比4比7,且2X-Y+Z=18那么X+2Y+3Z的值是多少?
答
X比Y比Z=3比4比7=k
x=3k y=4k z=7k
2X-Y+Z=9k=18 k=2
X+2Y+3Z=32k=64
答
X=3a
Y=4a
Z=7a
2X-Y+Z = 6a -4a +7a = 9a =18
a = 2
X=6
Y=8
Z=14
X+2Y+3Z = 6+16+42 = 64
答
设x、y、z分别为3k、4k、7k
所以6k-4k+7k=18
k=2
所以X+2Y+3Z=6+16+42=64