X^2 + 3x + 25 = 0
Since the quadratic equation is not factorable
Then use the quadratic formula to solve it
X = [- b + sqrt(b^2 – 4ac)] / 2a
and
X = [- b - sqrt(b^2 – 4ac) ]/ 2a
X = [- 3 + sqrt(3^2 – 4(1)(25))] / 2(1)
X = [- 3 + sqrt( - 91 ) ]/ 2
X = -3/2 + sqrt( 91)i/2
So the other solution
X = -3/2 - sqrt( 91)i/2