## Intermediate Algebra (6th Edition)

$$h = -16t^2-20t+180$$ We want to consider when h=50, so: $$0 = -16t^2-20t+130$$ We use the quadratic formula $$t= \frac{-b \pm \sqrt{b^2-4ac}}{2a}$$ Where b is the coefficient of the term with a variable raised to the first power, a is the coefficient of the squared term, and c is the coefficient of the term without a variable in front of it. We now solve, considering only the positive value, to have: t=2.3 s