<span>Thus you have a quadratic equation with two possible solution. Use the quadratic formula To calculate the x values. If you calculate it, you will find that x = 3.5 and x = -10.5. To prove which one is the width, substitute these values for x one at a time into the volume equation. Lets take x=3.5 </span>
<span>Therefore clearly, our answer will be x = 3.5... We don't have to use the substitution to prove our answer is 3.5 because logically we can rule out -10.5 inches of width. Realistically, there can never be a negative width. Therefore your width is 3.5 inches. Hopefully this helps!</span>
Since the equation is in the format, , in which h is the direction right and k is the direction up. Since the graph only goes up the equation structure should be . The equation is therefore, .
