1) Не разветвление)
program xizt;
uses crt;
var x,f:real;
begin
writeln ('введите х');
readln (x);
f:=sqr(x)-3;
writeln (f);
end.
2) program xizt;
uses crt;
var a,b,s:real;
begin
writeln ('введите a,b через пробел');
readln (a,b);
s:=1/2*a*b
writeln (s);
end.
3) program xizt;
uses crt;
var a,b,c:real;
begin
writeln ('введите a,b через');
readln (a,b);
c:=sqr(a)-sqr(b);
writeln (c);
end.