Well.. for the equation x= 3.5, let's take a look at its values

so.. notice.. no matter what "y" is, "x" will always be 3.5,
so is really just a horizontal line, thus, look at the picture below
Y-intercept when x = 0
so
y = 4
X = 23
x - 7
(23) - 7 = 16
16 is your answer
hope this helps
Answer:
1/2
Step-by-step explanation: