What is the input value for the following function if the output value is 2.4?

y = x + 1.6

0.8
1.6
1.8
4

If you would like to find the input value for the following function if the output value is 2.4, you can calculate this using the following steps:

output ... 2.4
y = x + 1.6 = 2.4
x + 1.6 = 2.4
x = 2.4 - 1.6 = 0.8

The correct result would be 0.8.