If you would like to know which of the following could not be the function equation, you can find this using the following steps:
input ... 4
output ... 10
y = x + 6 ... y = 4 + 6 = 10
y = 2x + 3 ... y = 2 * 4 + 3 = 8 + 3 = 11
y = 14 - x ... y = 14 - 4 = 10
y = (2.5)x ... y = (2.5) * 4 = 10
The correct result would be y = 2x + 3.
