The difference between the two given equations is that 1 is subtracted from 2x in the first equation while this is missing from the second. If we are going to add 1 to both sides of the first equation, we get the answer of,
y + 1 = 2x - 1 + 1
y + 1 = 2x
As we can see, the equation above is similar to y = 2x except that +1 is added to the y value. Thus, your graph is translated 1 unit up.