a,2x-6=22
=> 2x = 22 + 6
=> 2x = 28
=> x = 28 : 2
=> x = 14 thuộc Z
vậy____
b,(3x-1)-5=21
=> 3x - 1 = 21 + 5
=> 3x - 1 = 26
=> 3x = 26 + 1
=> 3x = 27
=> x = 27 : 3
=> x = 9 thuộc Z
Vậy____
bài 3 :
\(\frac{2}{4}=\frac{4}{8}=\frac{8}{16}=\frac{16}{32}\)
\(\frac{4}{2}=\frac{8}{4}=\frac{16}{8}=\frac{32}{16}\)
\(\frac{2}{8}=\frac{4}{16}=\frac{8}{32}\)
\(\frac{8}{2}=\frac{16}{4}=\frac{32}{8}\)
\(\frac{2}{16}=\frac{4}{32}\)
\(\frac{16}{2}=\frac{32}{4}\)