Question

 sqrt{5x+1} +3 x=0

Answer 1

$sqrt{5x+1}=-3x\ begin{cases} -3x geq0 \ 5x+1 geq 0\ 5x+1=9x^2 end{cases} <=> begin{cases} x leq0 \ x geq -0,2\ 9x^2-5x-1=0 end{cases} <=> begin{cases} -0,2 leq x leq 0 \ 9x^2-5x-1=0 end{cases} \ D=25+36=61\ x=dfrac{5pm sqrt{61}}{18}\ begin{cases} -0,2 leq x leq 0 \ x=dfrac{5pm sqrt{61}}{18} end{cases} => x=dfrac{5- sqrt{61}}{18} (approx -0,156)$
Ответ: $dfrac{5- sqrt{61}}{18}$