Right over here, I've defined a function f of x. It's equal to 2x everywhere except for x equals 5. It's 2x everywhere for all the other values of x, but when x is equal to 5, it's just equal to x. I could have really just written 5. I could have just written 5 there. It's equal to 5 when x is equal to 5. It's equal to itself. We've drawn the graph here.