If the line is vertical, then all of the point on the line have the same x-coordinate. In this case the x-coordinate is 1, so x=1.
Answer:

Step-by-step explanation:
How to factor expressions?
Find the G.C.F. and divide it into the terms of the expression you need to factor, like this:
. So I took the 12 and pulled it out of both terms, obtaining
.
Answer D). 9 ft is correct
Height of the ball at a horizontal distance of 10 feet is 9 ft
Step-by-step explanation:
A ball is thrown and it follows a parabolic path. At each horizontal distance (x) the following equation models the ball’s height (y).
Y(x) = 
Question asked is " What will be height (Y) of the ball when X=10 ft "
Simply putting value of X in given equation
we get,
Y(x) = 
Y(x) = 
Y(x) = 
Y(x) = 
Y(x) = 
<em>Therefore,</em> Height of the ball at a horizontal distance of 10 feet is 9 ft
Answer D. 9 ft is correct