[tex] \frac{7x + 21}{x + 2} = \frac{x + 3}{5} \\ 5(7x + 21) = (x + 3)(x + 2) \\ 5(7x + 21) - (x + 3)(x + 2) \\ 35x + 105 - ( {x}^{2} + 2x + 3x + 6) = 0 \\ 35x + 105 - {x}^{2} - 5x - 6 = 0 \\ 30x + 99 - {x}^{2} = 0 \\ - {x}^{2} + 30x + 99 = 0 \\ {x}^{2} - 30x - 99 = 0 \\ delta = 1296 \\ x1 = 33 \\ x2 = - 3[/tex]
