Cześć ;-)
b)
[tex]\frac{48}{49}:x=\frac{3}{49}\\\\x=\frac{48}{49}:\frac{3}{49}\\\\x=\frac{\not48^{16}}{\not49_1}\cdot\frac{\not49^1}{\not3_1}\\\\\huge\boxed{x=16}[/tex]
d)
[tex]\frac{48}{49}:x=\frac{8}{49}\\\\x=\frac{48}{49}:\frac{8}{49}\\\\x=\frac{\not48^6}{\not49_1}\cdot\frac{\not49^1}{\not8_1}\\\\\huge\boxed{x=6}[/tex]
Pozdrawiam!