Đề bài dạng như thế này à ?
\(\frac{3}{4}\times y+25\%\times y+y:0,5=31,5\)
=> \(\frac{3}{4}\times y+\frac{25}{100}\times y+y:\frac{5}{10}=31,5\)
=> \(\frac{3}{4}\times y+\frac{1}{4}\times y+y\times\frac{10}{5}=31,5\)
=> \(\frac{3}{4}\times y+\frac{1}{4}\times y+y\times2=31,5\)
=> \(y\times\left(\frac{3}{4}+\frac{1}{4}+2\right)=31,5\)
=> \(y\times3=31,5\)
=> \(y=31,5:3=10,5\)
Vậy y = 10,5