Answer:
shifted down 4 units
Explanation:
You want to know the effect on the graph of changing y=2x+2 to y=2x-2.
Y-intercept
The constant in the equation y=2x+2 is the y-intercept. The line described by this equation crosses the y-axis at y=2.
When the equation is changed to y=2x-2, the y-intercept changes from +2 to -2, a shift down of 4 units. The shifted line has the same slope as the original, so is parallel to it.
The effect on the graph is to move it down 4 units.