B1:
uses crt;
var a:longint;
begin
clrscr;
write('Nhap a=');readln(a);
if a>=0 then write(a,' khong am')
else write(a,' am');
readln;
end.
B2:
uses crt;
var a,b:longint;
begin
clrscr;
write('Nhap a=');readln(a);
write('Nhap b=');readln(b);
if (a=0) and (b=0) then write('Phuong trinh vo so nghiem');
if (a=0) and (b<>0) then write('Phuong trinh vo nghiem')
else write('Phuong trinh co nghiem x=',-b/a:0:2);
readln;
end.