In this question it is given that Samuel tosses a football from the top of a hill. The football's height h, in feet, after t seconds is modeled by the equation

When football reach the ground, then value of h is 0 .
So we have to put 0 for h and solve for t. That is



Dividing both sides by 4 to get rid of 4




And time cant be negative. SO the time by which football reach the ground is 3/2 or 1.5 seconds .