Question

Calcule o valor da incógnita em cada caso:


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Answer 1

a)

$\frac{x}{15}=\frac{2}{3}\\\\\frac{15x}{15}=\frac{2\cdot \:15}{3}\\\\\frac{15x}{15}=x\\\\\frac{2\cdot \:15}{3}\\\\=\frac{30}{3}\\\\=10\\\\x=10$

b)

$\frac{7}{x+4}=\frac{2}{6}\\\\7\cdot \:6=\left(x+4\right)\cdot \:2\\\\42=\left(x+4\right)\cdot \:2\\\\\left(x+4\right)\cdot \:2=42\\\\\frac{\left(x+4\right)\cdot \:2}{2}=\frac{42}{2}\\\\x+4=21\\\\x+4-4=21-4\\\\x=17$