Question

preciso de ajuda, pfv​

Answer 1

Resposta:

a) $x^{2} -91=31\\x^{2} =122\\x=\sqrt{122}$

b) $5x^{2} +4=49\\5x^{2} =49-4\\x^{2} =\frac{45}{5} \\\\x=\sqrt{9} \\x=3$

c)$4x^{2} -27=x^{2} \\4x^{2} -x^{2} =27\\\\x^{2} =\frac{27}{3} \\\\x^{2}=\sqrt{9}  \\x=3$