Factor completely x2 + 25

(x - 5i) (x + 5i)

Step-by-step explanation:

Write this as x^2 + 25. Solving for x^2, we get x^2 = - 25.

Recall that the square root of a negative number is an imaginary one. √ (-25) equals ±5i (there are two roots, one positive and one negative).

Then x = ±5i.

In factored form, the given expression is (x - 5i) (x + 5i).