So check the picture below
if we check the solutions or zeros for the equation, we get

and as you can see in the picture, the value of "x" when y = 3.5, or the height of the truck is

the truck, ends up with a clearance of

on either side, so, the maximum clearance, the truck can have, those two clearances added together,
F - Irrational, -13.8
Because the negative sign is not inside of the radical, we can tell that the number is being multiplied by the negative. Thus, do the radical equation first, get the answer 13.8202... and multiply by -1 to get the answer. Also, it is irrational because it is not a perfect square.
Uhhh , what are we suppose to answer here ?
Answer:
(x,y) becomes (-y,x) so (3,2) would become (-2,3)
X/7 = 6/4.2
4.2x = 42
x= 10