Question

resolva as equações do 2 grau
9x²-5=0
21=7x²

Answer 1

9x²-5=0
9x²=5
x²=$\frac{5}{9}$
x=$\sqrt{ \frac{5}{9} }$
x=$\frac{ \sqrt{5} }{3}$

21=7x²
x²=3
x=$\sqrt{3}$