Question

Х=7(х+3)\3х+5 найдите корень уравнения

Answer 1

$x= \frac{7(x+3)}{3x+5} \\ 7x+21=x(3x+5) \\ 7x+21=3x^2+5x \\ 3x^2-2x-21=0 \\ D=4+252=256=16^2 \\ x1= \frac{2-16}{6}= \frac{-14}{6}= -2 \frac{1}{3} \\ x2= \frac{2+16}{6}= \frac{18}{6} = 3$