How do you solve 7x^2+5x+8=0 using the quadratic formula?

1 Answer
Jul 31, 2016

No real roots.

Explanation:

Use the new quadratic formula in graphic form (Socratic Search)
y = 7x^2 + 5x + 8 = 0
D = d^2 = b^2 - 4ac = 25 - 224 = - 199 < 0
Because D < 0, there are no real roots.

Note. There are 2 complex roots. d = +- isqrt199
x = -b/(2a) +- d/(2a) = -5/14 +- (isqrt199)/14 = (- 5 +- isqrt199)/14