Question

$4x {}^{2} - 9 = 7$

Answer 1

$4 {x}^{2} - 9 = 7 \\ 4 {x}^{2} = 7 + 9 \\ 4 {x}^{2} = 16 \\ {x}^{2} = 4 \\ x = ±2 \\ x = - 2 \\ x = 2$

Respuesta:

$x_{1} = - 2 . \: \: \: x_{2} = 2$