`a// y+2/9=1`
`y=1-2/9`
`y=9/9-2/9=7/9`
`b// y-1/2=1/4`
`y=1/4+1/2`
`y=1/4+2/4=3/4`
a, <=> y = 1 -2/9 = 7/9
b, <=> y = 1/4 + 1/2 = 3/4
`y+2/9=1`
`y=1-2/9`
`y=9/9-2/9`
`y=7/9`
`y-1/2=1/4`
`y=1/4+1/2`
`y=2/8+4/8`
`y=6/8`
Bài 4:
a). \(y+\dfrac{2}{9}=1\)
\(y=1-\dfrac{2}{9}\)
\(y=\dfrac{9}{9}-\dfrac{2}{9}\)
\(y=\dfrac{7}{9}\)
b). \(y-\dfrac{1}{2}=\dfrac{1}{4}\)
\(y=\dfrac{1}{4}+\dfrac{1}{2}\)
\(y=\dfrac{1}{4}+\dfrac{2}{4}\)
\(y=\dfrac{3}{4}\)
