Hello, Nimmy,Originally Posted byNimmy

I've attached a diagram to show you what you have to calculate:

In short: There are 2 points which are connected by a straight line. So you know 2 points of this line. Use the 2-point-formula of a line to get the equation.

(You should get f(x)=-x+1, -1 < x < 3)

Greetings

EB