Question

The quadratic function of d = 7x^2 + 80 models a ball’s distance, in feet from the bottom of the hill x seconds after the ball is rolled down the hill. I know the answer is (approximately) 3.4, but how do I get to there without a graph

Answer 1

3.38

Explanation:

Set the equation given equal to 0 and solve for x, this will give you the distance the ball travels. Use the absolute value of the 80 to be able to get a positive number, because time is a positive number.

`0=7x^2+80\\7x^2=-80\\x=\sqrt{(80)/(7)\\\\x=3.38062`