When you add a positive number to the equation after the function, the "V" (where both lines meet and stop) would begin on the positive number given on the y-axis, and same for when you subtract a number from the equation after the function. The "V" would start on the y-axis on that negative number that was given.
When you add a positive number to X before performing the equation, the "V" would start on the negative value of the positive number on the x-axis, and one of the lines of the 'V" would pass through that positive number given on the y-axis. Like before, about the same thing would happen if you were to subtract a number from X before performing the equation. The point of the "V" would start on the positive value of the negative number given on the x-axis, and one side of the "V" would pass through the positive value of it on the y-axis.