Step-by-step explanation:
[tex] {x}^{2} - 2x - 8 = 7[/tex]
[tex] {x}^{2} - 2x - 8 - 7 = 0[/tex]
[tex] {x}^{2} - 2x - 15 = 0[/tex]
[tex] {x}^{2} - 5x + 3x - 15 = 0[/tex]
[tex]x(x - 5) + 3(x - 5) = 0[/tex]
[tex](x - 5)(x + 3) = 0[/tex]
[tex]x = 5 \: \: or \: \: x = - 3[/tex]
