Update HOME_EXAM.md

HOME_EXAM.md

@@ -540,10 +540,6 @@ let d:bool = *b; // <-- Type missmatch
 ```
 
 #### Function call
-```math
-\frac{<f(e), σ> → t}{<f, σ> → \text{ret } t}
-```
-
 ```math
 \frac{<e_1, σ> → <t_1, σ^1> ... <e_n, σ^{n-1}> → <t_n, σ^n> <f_{call}, σ^n[p_1=t_1, ..., p_n=t_n]> → <t_{res}, σ'>}{<f(e_1, ..., e_n), σ> → <f_t, σ'>}
 ```