x/6:1/4=2/7:4/21 x=?
问题描述:
x/6:1/4=2/7:4/21 x=?
答
x/6:1/4=2/7:4/21
x/6×4/21=1/4×2/7
2x/63=1/14
2x=1/14×63
2x=9/2
x=9/2÷2
x=9/4