Explicación paso a paso:
[tex]x(x + 3) = 5x + 3 \\ {x}^{2} + 3x = 5x + 3 \\ {x}^{2} + 3x - 5x - 3 = 0 \\ {x}^{2} - 2x - 3 = 0 \\ x + x - 3x - 3 = 0 \\ x(x + 1) - 3(x + 1) = 0 \\ (x + 1) \times (x - 3) = 0 \\ \\ x + 1 = 0 \\ x - 3 = 0 \\ \\ x = - 1 \\ x = 3[/tex]
