Let's factor: f(b) = 9b² - 5b - 10
Using the quadractic equation we have:
b = (5 +/+ √25 - 4 * -10 * -9)/18
b = (5 +/- √385)/18
b1 = (5 + 19.62)/18
b2 = (5 - 19.62)/18
b1 = 1.37
b2 = -0.81
