Find k if f x =2x+1,x<2 is continous at x =2;?

Get out of the habit of hitting the Shift key just because you start a new line. K is not k and a math program will not tell you that you made a mistake, it will just give you goofy results.

Your question does not suggest any particular answer because K and k are undefined, and the overall statement is incorrectly presented (x < 2 contradicts x = 2).

The term "f of x" is written f(x), assuming that is what you meant.

Remember not everybody knows what you are talking about, so add spaces to your statements to prevent it from running together. Like this:

Find k if f(x) = 2x + 1, x < 2 is continuous at x = 2? ("continuous" spelling corrected, unneeded semicolon deleted.)

In math, mistrakes kill people. You have to get it right the first time.