Question

como se faz essa equação.a) 5x2+20=25.B) 9X2_18=0.

Answer 1

$A) ~~5x^2+20=25\to\\\\ 5x^2=25-20\to\\\\ 5x^2=5\to\\\\ x^2= \dfrac{5}{5} \to\\\\ x^2=1\\\\ x=\pm~ \sqrt{1} \to\\\\ x=\pm~1\\\\\\ \large\boxed{S=\{ -1~;~1\} }$





$B) ~~9 x^{2} -18=0\to\\ \\9 x^{2}=18\to\\ \\ x^{2} = \dfrac{18}{9} \to\\\\ x^{2} =2\to\\\\ x=\pm~ \sqrt{2} \\\\ \\\large\boxed{S=\{-\sqrt{2}~;~\sqrt{2}\} }$