Question

If x∈R and x=√(x+20), then x=?​

Answer 1

Answer:

consider x, then

x = √x + 2√5

squaring on both sides,

x^2 = (√x)^2 + (2)^2 . (√5)^2

x^2 = x + 4 × 5

x^2 = x +20

x = x^2 - 20

0 = x^2 - x - 20. ( splitting the middle term)

0 = x^2 + 4x -5x -20

0 = x(x + 4) -5 (x+4)

0 = (x +4) × (x - 5)

Therefore,

x = -4

x = 5