C4:
a. m-n*n<>0
b. sqr(u+2)/12
c. 2*(a+b*b)<=0
d. 2*x*y>=5
C5:
uses crt;
var x, y: integer;
a, b, T: real;
begin
clrscr;
write('Nhap x = '); readln(x);
write('Nhap y = '); readln(y);
write('Nhap a = '); readln(a);
write('Nhap b = '); readln(b);
writeln('So tien cua x loc sua la: ', x*a*15/100);
writeln('So tien cua y goi keo la: ', y*b*15/100);
T:=x*a*15/100+y*b*15/100;
writeln('So tien An phai tra la: ', T);
readln
end.