2x^2 - 5x - 35 = 0
quadratic formula
x = (5 +- sqrt((-5)^2 - 4(2)(-35)))/2(2)
x = (5 +- sqrt(25 + 280))/4
x = (5 +- sqrt(305))/4
x = (5 +- sqrt(5*61))/4
5 and 61 are prime, so there's nothing to factor out of the sqrt.
Answer: x = (5 + sqrt(5*61))/4 or x = (5 - sqrt(5*61))/4