Question

resolva a equaçao do 2grau:
7x2-21=0

Answer 1

x2= 21/7

x2=3

X = mais ou menos raiz quadrada de 3.

Answer 2

$7x^2-21=0=\ \textgreater \ x^2= \frac{21}{7} =\ \textgreater \ x= +-\sqrt{3}$