uses crt; var a,b,c:longint; d:real; begin clrscr; writeln('Giai phuong trinh: ax^2+bx+c=0'); write('Nhap a=');readln(a); write('Nhap b=');readln(b); write('Nhap c=');readln(c); d:=sqr(b)-4*a*c; if d<0 then writeln('Phuong trinh vo nghiem'); if d=0 then writeln('Phuong trinh co nghiem duy nhat x=',-b/(2*a):0:2); if d>0 then begin writeln('Phuong trinh co 2 nghiem phan biet'); writeln('x1=',(-b-sqrt(d))/(2*a):0:2); writeln('x2=',(-b+sqrt(d))/(2*a):0:2); end; readln; end.
uses crt; var a,b,c:longint; delta:extended; begin clrscr; write('Nhap a,b,c: '); readln(a,b,c); delta:=b*b-4*a*c; if delta<0 then writeln('PT vo nghiem.') else if delta=0 then writeln('PT co nghiem kep: x1=x2=',-b/(2*a):0:2) else begin writeln('PT co 2 nghiem phan biet: x1=',(-b+sqrt(delta))/(2*a):0:2); writeln(' x2=',(-b-sqrt(delta))/(2*a):0:2); end; readln; end.
