what is the equation if the input is 2 the out put is 7 the input is 3 the out put is 10

There are many possible answers.

Here is one of them:

You might notice that if you multiply the input by 3 and then add one, you can get the output.

--->   2 x 3 + 1  =  7

--->   3 x 3 + 1  =  10

--->   input x 3 + 1  =  output