Question

Help Me! Tá difícil ​

Answer 1

Explicação passo a passo:

$a) \frac{4}{5} = \frac{6}{x} \\4x = 30 \\x = \frac{30}{4} = \frac{15}{2} \\\\b) \frac{x + 1}{3} = \frac{x + 5}{2x} \\3x + 15 = 2x^{2} +2x\\2x^{2} - x - 15 = 0 \\x' = \frac{1+\sqrt{(-1)^{2} - 4.2.(-15) } }{2.(2)} = \frac{1 + \sqrt{121} }{4} = \frac{12}{4} = 3\\ x'' = \frac{1-\sqrt{(-1)^{2} - 4.2.(-15) } }{2.(2)} = \frac{1 - \sqrt{121} }{4} = \frac{-10}{4} = \frac{-5}{2}$