Giải Phương Trình Bậc 2

Program giaiptbac2;
uses crt;
var a,b,c,d : real;
begin
write(‘nhap he so a: ‘); readln(a);
write(‘nhap he so b: ‘); readln(b);
write(‘nhap he so c: ‘); readln(c);
d:=b*b-4*a*c
if (d<0) and (a<>0) then write(‘phuong trinh da cho vo nghiem’);
if (d=0) and (a<>0) then write(‘nghiem cua phuong trinh la X1=X2=’,-b/(2*a));
if (d>0) and (a<>0) then begin
write(‘nghiem cua phuong trinh la X1=’,(-b+sqrt(d))/(2*a));
write(‘nghiem cua phuong trinh la X2=’,(-b-sqrt(d))/(2*a));
end;
if (a=0) and (b<>0) then write(‘nghiem cua phuong trinh la x=’,-c/b);
if (a=0) and (b=0) and (c=0) then write(‘phuong trinh da cho co vo so nghiem’);
if (a=0) and (b=0) and (c<>0) then write(‘phuong trinh da cho vo nghiem’);
readln
end.