[tex]x + y = 99 \\ x \div \frac{y}{4} = 5 \\ x \times \frac{4}{y} = 5 \\ \frac{4x}{y} = 5 \\ x = \frac{5y}{4} \\ x + y = 99 \\ \frac{5y}{4} + y = 99 \: \: | \times 4 \\ 5y + 4y = 396 \\ 9y = 396 \\ y = 44 \\ x = \frac{5y}{?4} = \frac{5 \times 44}{4} = 55 \\ x = 55[/tex]
verificare: 44+55=99
coroana?
