Solve for x:
sqrt(x + 15) = 15 - sqrt(x)
Raise both sides to the power of two:
x + 15 = (15 - sqrt(x))^2
Subtract (15 - sqrt(x))^2 from both sides:
15 - (15 - sqrt(x))^2 + x = 0
15 - (15 - sqrt(x))^2 + x = 30 sqrt(x) - 210:
30 sqrt(x) - 210 = 0
Add 210 to both sides:
30 sqrt(x) = 210
Divide both sides by 30:
sqrt(x) = 7
Raise both sides to the power of two:
Answer: | x = 49