Respuesta :

Answer:

100

Step-by-step explanation:

[tex] {x}^{2} + 20x + c \\ \\ {x}^{2} + 2.x.10 + {10}^{2} \\ {x}^{2} + 20x + 100 \\ \implies \: {x}^{2} + 20x + c \\ \implies \: c = 100[/tex]