x = +/- sqrt(225) = +/- 15

No solution.]

2. x^2 = -225

a^2 - 64 thus, a^2 = 643. a^2 - 64 = 0

a = +/- sqrt(64) = +/- 8

3n^2 = 75 thus, n^2 = 254. 3n^2 - 75 = 0

n = +/- sqrt(25) = +/- 5

n^2 = 6. n^2 - 6 = 0

n = +/- sqrt(6)

(n-5) = +/- sqrt(20) = +/- 2*sqrt(5)6. (n - 5)^2 = 20

n = 5 +/- 2*sqrt(5)