[tex](x - 1)(x - 7) = 0 [/tex]
[tex] {x}^{2} - 8x + 7 = 0[/tex]
[tex] {x}^{2} - 8x = - 7[/tex]
[tex] - 7x = \frac{ - 7}{x} [/tex]
[tex]x = \frac{ - 7}{ \frac{x}{ - 7} } \implies x = x \implies x \in \mathbb{R}[/tex]
x is true for any number in real domain.
