Question 33225
x = {{{sqrt(x+20)}}}
square both sides
{{{x^2}}}= (x+20)
{{{x^2}}}- x -20 = 0
{{{x^2}}}-5x +4x - 20 =0
x(x-5)+4(x-5)= 0
(x+4)(x-5) = 0
x = -4 or x = 5