Chapter 5 - Polynomials and Factoring - 5.8 Solving Applications - 5.8 Exercise Set - Page 360: 29

10

We are given the following equation: $$ H=.03x^2+.6x-6$$ Plugging in 3 for H, we find: $$3=0.03x^2+0.6x-6 \\ 3x^2+60x-900=0 \\ x_{1,\:2}=\frac{-60\pm \sqrt{60^2-4\cdot \:3\left(-900\right)}}{2\cdot \:3} \\ x=10$$ Wind speeds can only be positive.