Respuesta :

In general you want a number x such that

[tex](x+20)^2 = 36\\[/tex]

Resolving this you obtain two solutions.

[tex](x+20)^2 = 36\\x + 20 = \pm 6\\x = \pm 6 - 20\\x_1 = -14, x_2 = -26.[/tex]

So...