Question 754841
s^2+5s=-1
add (b/2)^2 = (5/2)^2 = 25/4 to both sides:
s^2+5s+25/4=-1+25/4
(s+5/2)^2 = -1+25/4
(s+5/2)^2 = -4/4 + 25/4
(s+5/2)^2 = 21/4
s+5/2 = +-sqrt(21/4)
s+5/2 = +-(1/2)sqrt(21)
s = -5/2 +- (1/2)sqrt(21)