Answer:
x = -8, x = 5
Step-by-step explanation:
This can be solved using Factorization method:
[tex] 40 = 3x + {x}^{2} \\ \\ \implies \: {x}^{2} + 3x - 40 = 0 \\ \\ \implies \: {x}^{2} + 8x - 5x- 40 = 0 \\ \\ \implies \: x({x} + 8) - 5(x + 8) = 0 \\ \\ \implies \: ({x} + 8) (x - 5) = 0 \\ \\ \implies \: ({x} + 8) = 0 \: \: or \: \: (x - 5) = 0 \\ \\ \implies \: x = - 8 \: \: or \: \: x = 5 \\ \\ x = - 8, \: \: 5[/tex]
