How do you solve for the y-intercept is $2x - y = 4$?

Hint: First we will take all the like terms to one side and then all the alike terms to the other side that converts this equation to slope point form of a line. After that, we will compare the terms of the equation with the slope point form of the equation and evaluate the value of y-intercept.

Complete step by step answer:
 We will start by rearranging the terms that is all the like terms to one side and all the alike terms to the other side.
$
  2x - y = 4 \\
  2x - 4 = y \\
 $
So, the equation will finally become, $y = 2x - 4$.
Now we will compare this equation to the slope point form of the line which is $y = mx + c$.
After comparing the values, we get the values of the terms as:
$
  m = 2 \\
  c = - 4 \\
 $
In the slope point form equation $y = mx + c$, $c$ represents the y-intercept of the line.
So, here the y-intercept of the line is $ - 4$.
Additional information: In analytic geometry, using the common convention that the horizontal axis represents a variable x and the vertical axis represents a variable $y$, a y-intercept or vertical intercept is a point where the graph of a function or relation intersects the y-axis of the coordinate system.

Note:
While rearranging the terms, make sure you arrange all the like terms separately and all the like terms separately with their respective signs. When you compare the terms make sure you are comparing the terms with their signs as if you will not take into account the sign it will give you an incorrect answer.