Câu 1:
a. 2*x*y+x*x>=0
b. sqr(m+n)<>m*m+n*n
Câu 2:
program dt_hinh_thang;
uses crt;
var a, b, h, dt;
begin
clrscr;
write('Nhap a = '); readln(a);e
write('Nhap b = '); readln(b);x
write('Nhap h = '); readln(h);c
dt:=(a+b)/2*h;s
writeln('Dien tich hinh thang do la: ', dt);
readlnerlska
end.