Solve

s2 + 5s + 7 = 0

Please use a ^ symbol before exponents.

s^2 + 5s + 7 = 0

In that equation, the coefficients of the three terms are
a=1, b=5, and c = 7

Use this formula for the answer:

s = [-b +/- sqrt (b^2-4ac)]/2a

Just plug in the numbers. You will get complex roots in this case, since b^2-4ac = -3 <0.