Помогите с информатикой пожалуйста

 program p56; 
var X,F: real; 
begin 
Readln(X); 
if X<=7 then F:=-3*X+9 
        else F:=1/(X-7); 
Writeln(F) 
end. 
 
 
program p57; 
var X,F: real; 
begin 
Readln(X); 
if X<=7 then F:=3*X-9 
        else F:=1/(X*X-4); 
Writeln(F) 
end. 


program p58; 
var X,F: real; 
begin 
Readln(X); 
if (0<=X) and (X<=3) then F:=X*X 
                     else F:=4; 
Writeln(F) 
end.
 

program p59; 
var X,F: real; 
begin 
Readln(X); 
F:=X*X+4*X+5; 
if X>2 then F:=1/F; 
Writeln(F) 
end.