Question

What rule changes the input numbers to output numbers?

Answer 1

do you know how to find the equation of a line given two points?

Answer 2

no

Answer 3

is it discrete maths ?

Answer 4

I don't know what that is.
I just have to find it the rule

Answer 5

So, the inputs are 1,2,3,4. You want to find a pattern in the outputs. How does -2 turn into 1?
How does 1 turn into 4? How does 4 turn into 7? Multiplying would require a different multiplier each time, but adding 3 every time works. You have what is called an arithmetic sequence here, or a linear function, in other words.

Since you have a multiple choice, you could just put 1 into each answer and see which ones give you -2. And likewise with the others, so there is only one answer.