A 50% increase is just taking the original amount and adding half of that towards the amount.
Example : 50% of 100 is 50 so a 50% increase to 100 would be 150
a formula for this would be X + (1/2×X) = Y
in your case we're working backwards with the known being 60
We can just plug in reasonable values for X until we get 60
50% of 40 is 20
40 + 20 = 60
so the original amount was 40
Answer: Linear
It is linear because you can subtract 1 from both sides to get y = 5x-1
That equation is in the form y = mx+b
m = 5 is the slope
b = -1 is the y intercept
If your adding its 17, Subtracting its 7, multiplying its 60 and dividing its 2.4 hope this helps