Question

For (x - 1)(x - 7) to equal 0, either (x - 1) or (x - 7) must equal what?

Answer 1

$(x - 1)(x - 7) = 0$

${x}^{2} - 8x + 7 = 0$

${x}^{2} - 8x = - 7$

$- 7x = \frac{ - 7}{x}$

$x = \frac{ - 7}{ \frac{x}{ - 7} } \implies x = x \implies x \in \mathbb{R}$

x is true for any number in real domain.