Question

determine os valores de x e y nos seguintes feixes de paralelas:

Answer 1

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a)
$\frac{2}{5} = \frac{x}{y} \\ x+y=2 \\ x=2-y \\ \\ \frac{2}{5} = \frac{2-y}{y} \\ \\ 2y=5(2-y) \\ 2y=10-5y \\ 2y+5y=10 \\ 7y=10 \\ \\ y= \frac{10}{7} \\ \\ se~x=2-y \\ x=2- \frac{10}{7} \\ \\ x= \frac{14-10}{7} \\ \\ x= \frac{4}{7}$


b)
$\frac{4}{9} = \frac{x}{y} \\ x+y=52 \\ x=52-y \\ \\ \frac{4}{9} = \frac{52-y}{y} \\ \\ 4y=9(52-y) \\ 4y=468-9y \\ 4y+9y=468 \\ 13y=468 \\ y=468\div13 \\ y=36 \\ \\ se~~x=52-y \\ \\ x=52-36 \\ \\ x=26$