Question

 x²+9x=0
quem responde pra min

Answer 1

x²+9x=0
fator comum
x(x+9)=0
x=0
x+9=0
x=-9
logo as raizes sao 0 e9

Answer 2

$x^2+9x=0 \\ \\ x*(x+9) = 0 \\ \\ \boxed{x=0} \\ \\ x+9 = 0 \\ \\ \boxed{x=-9} \\ \\ S=\{-9,0\}$

Espero ter ajudado. :))