1.

program ct;
uses crt;
var x: real;
begin
    clrscr;
    writeln('Nhap x:'); readln(x);
    writeln;
    if x <= 0 then 
        writeln('x khong phai so duong')
    else
        writeln('Can 2 cua x la: ',sqrt(x):5:3);
    readln
end.

2.

Program chisokhoi; 
Uses crt;
Var h, w, BMI: Real; 
    a: string; 
Begin 
    Clrscr; 
    Writeln ('Nhap can nang (kg):'); Readln(w);
    Writeln ('Nhap chieu cao (m):'); Readln(h); 
    BMI := w/ (h*h); 
    Writeln ('BMI =', BMI:5:2); 
    if BMI<8.5 then a:='Ban om';
    if (BMI>=8.5) and (BMI<25) then a:='Ban binh thuong';
    if (BMI>25) then a:='Ban map';
    writeln(a);
    readln;
End. 

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#Duahauvn

Bài 1 : 

uses crt;

var  x : real;

begin

clrscr;

write('nhap so thuc x :');readln(x);

if x > 0 then writeln('can bac hai cua ', x:3:1 ,' : ', sqrt(x):3:1) 

else writeln(x,' khong phai so duong');

readln

end.

Bài 2 :

uses crt;

var w, h, bmi : real;

begin

clrscr;

write('nhap chieu cao cua co the (met) :');readln(h);

write('nhap can nang cua co the (kg)  :');readln(w);

bmi := w/(h*h);

writeln('chi so BMI la :', bmi:8:2);

if bmi < 18.5 then writeln(' om');

if (bmi >=18.5) and (bmi < 25) then writeln('can doi');

if (bmi >= 25) then writeln('beo phi');

readln

end.