Answer:
x = -15/2 ± (1/2)*5√5
Step-by-step explanation:
I will assume that you meant x^2+15x+25=0.
To complete the square, take half of the coefficient of x, square the result, add this square into the equation after '15x,' and then subtract the square from the result:
x^2+15x+25=0 => x^2 + 15x + (15/2)^2 - (15/2)^2 + 25 = 0.
Rewrite the first two terms as (x + 15/2)^2 - 225/4 + 100/4 = 0, or
(x + 15/2)^2 - 125/4 = 0
Taking the square root of both sides, we obtain the solutions:
x + 15/2 ±√[125/4], or
x = -15/2 ± (1/2)*5√5
