Question

как сделать 25.38(б)

Answer 1

$x { }^{2} - x - 13x - 13 = 0 \\ x(x + 1) - 13(x + 1) = 0 \\ (x + 1)(x - 13) = 0 \\ x + 1 = 0 \\ x - 13 = 0 \\ x = - 1 \\ x = 13$