Hypergeometric function $\,_1 F_1(0;0;x)$?

Question

What is $\,_1F_1(0;0;x)$? Since its first argument is $0$, either we say it is 0 or since its first and second arguments are equal we say it is $e^x$? I cannot understand.

Answer 1

The function is constant: $$ \,_1F_{1}(0;0;x) = 1 $$

The exponential form comes from $$ \,_1F_{1}(1;1;x) = e^{x} $$

From functions.wolfram.com

Note the special case you ask about:

You have focused on a special case of $b=0$. From WolframMathworl: