Question

Sistema: {a/3 = b/4 {3a + 4b =20

Answer 1

Explicação passo-a-passo:

${\frac{a}{3} = \frac{b}{4} \\\ 3a + 4b = 20} \\\\[tex] 4a = 3b \\\ a = \frac{3b}{4} \\\\ 3.\frac{3b}{4} + 4b = 20 \\\ \frac{9b}{4} + 4b = 20 \\\ \frac{25b}{4} = 20 \\\ 25b = 80 \\\ b = \frac{80}{25} \\\\ b = \frac{16}{5} \\\\ a = \frac{3.\frac{16}{5}}{4} \\\\ a = \frac{3.\frac{16}{20}} \\\\ a = \frac{12}{5}$

Espero ter ajudado.