It would be 2x-20. Explanation: for inverse’s, you flip the y and the x and then solve for y to get your inverse. So, the equation would look something like
X = 1/2 y +10
I would then subtract 10 from both sides
X - 10 = 1/2 y
And then to get y by itself, you must multiply both sides by 2
2x - 10 • 2 = y
Getting the equation
2x- 20 = y