Ta có \(\frac{1+3y}{12}=\frac{1+6y}{16}\)

\(=>\frac{2\left(1+3y\right)}{24}=\frac{1+6y}{16}\)

\(=>\frac{2+6y}{24}=\frac{1+6y}{16}\)

Áp dụng tính chất dãy tỉ số bằng nhau

\(=>\frac{2+6y}{24}=\frac{1+6y}{16}=\frac{2+6y-\left(1+6y\right)}{8}=\frac{2+6y-1-6y}{8}=\frac{1}{8}\)

\(=>\frac{1+6y}{16}=\frac{1}{8}\)

\(=>8\left(1+6y\right)=16\)

\(=>8+48y=16\)

\(=>48y=8\)

\(=>y=\frac{1}{8}\)

Ta có

\(\frac{2+6y}{24}=\frac{1+6y}{16}=\frac{1}{8}\)

\(=>\frac{1+9y}{4x}=\frac{1}{8}\)

Thế \(y=\frac{1}{6}\) vào biểu thức ta có

\(\frac{1+9y}{4x}=\frac{1}{8}\)

\(=>\frac{1+9.\frac{1}{6}}{4x}=\frac{1}{8}\)

\(=>\frac{\frac{5}{2}}{4x}=\frac{1}{8}\)

\(=>20=4x\)

\(=>x=5\)

vio ak? z lấy kết quả thui nha!

x = 5

x=5

Ta có : \(\frac{1+3y}{12}=\frac{1+6y}{16}=\frac{1+9y}{4x}\)

\(\Rightarrow\frac{1+3y}{12}=\frac{1+9y}{4x}=\frac{1+3y+1+9y}{12+4x}=\frac{2+12y}{12+4x}\)

\(\Rightarrow\frac{1+6y}{16}=\frac{2.\left(1+6y\right)}{12+4x}\)

Do đó : \(16=\frac{12+4x}{2}\)

Từ đó suy ra : x = 5

\(\frac{1+3y}{12}=\frac{1+6y}{16}\)

<=> (1 + 3y).16 = (1 + 6y).12

<=> 16 + 48y = 12 + 72y

<=> 16 - 12 = 72y - 48y

<=> 24y = 4

<=> y = 1/6

Thay y = 1/6 vào đề bài ta được:

\(\frac{1+3.\frac{1}{6}}{12}=\frac{1+9.\frac{1}{6}}{4x}\)

\(\Leftrightarrow\frac{\frac{3}{2}}{12}=\frac{\frac{5}{2}}{4x}\Leftrightarrow6x=30\Leftrightarrow x=5\)

Vậy x = 5; y = 1/6

\(\frac{1+3y}{12}=\frac{1+6y}{16}=\frac{1+9y}{4x}\)

\(\Leftrightarrow12\left(1+6y\right)=16\left(1+3y\right)\)

\(\Leftrightarrow3\left(1+6y\right)=4\left(1+3y\right)\)

\(\Leftrightarrow3+18y=4+12y\)

\(\Leftrightarrow3-4=12y-18y\)

\(\Leftrightarrow-1=-6y\)

\(\Rightarrow y=\frac{1}{6}\)

\(\Rightarrow\frac{1+3y}{12}=\frac{1+3.\frac{1}{6}}{12}=\frac{1+9.\frac{1}{6}}{4x}\)

\(\Leftrightarrow\frac{\frac{3}{2}}{12}=\frac{\frac{5}{2}}{4x}\)

\(\Leftrightarrow\frac{1}{8}=\frac{\frac{5}{2}}{4x}\)

\(\Rightarrow4x=8.\frac{5}{2}=20\)

\(\Rightarrow x=20:4=5\)

Vậy \(x=5\)