You first of all plot the line x = 7.

Since it says "x equals seven". Go out to where 'x equals 7' 
on the x-axis, and draw a vertical line through it, like the
green one below:



Now plot the point (-4,3), which is the red point below:

 

Now draw a red line through it parallel to it..

 

Now think about this.  If the green line's equation is 

x = 7 

because it is a vertical line that goes through the point 
on the x-axis where x equals 7,

Then what would you suspect the equation of a vertical line
that goes through the point on the x-axis where x equals -4,
would be?

Answer:  x = -4

If you're wondering about the 3 in (-4,3)? and why you did
nothing with it, just realize that the line would have been 
the same line regardless of what number was where the 3 is.

Edwin