The x-intercept is defined to be the value of x when y is zero. Based on the graph of the function: f(x) = (x-4)(x+4), the x-intercepts are located at (-4, 0) and (4,0). At these points the graph intersects the x-axis. The midpoint of the x-intercepts is located at the middle of the two points. In this case, the graph shows that it is at the origin or at (0,0).
First, convert all measurements to inches.
Box 1:
3ft(12in)=36in+6in=42in
Box 2:
4ft(12in)=48in+10in=58in
Box 3:
4ft(12in)=48in+5in=53in
Now, add the heights together.
42in+58in+53in=153in
Finally, convert added height to feet.
153in/12in=12 with a remainder of 9, so your final answer is 12ft 9in