a. (a/b) * (a/b)* x/y

b. b/(a*a/c)

c. 1/(1/2)/(1/(2*3))/(1/(3*4))/(1/(4*5))

1.

a. sqr(a+b)-x/y

b. b/(a*a+c)

c. a*a/(sqr(2*b+c))

d. 1+1/2+1/2*3+1/2*4+1/2*5

2.

program btsydn;

uses crt;

  var a, b: real;

begin

          clrscr;

          write('Nhap chieu dai = '); readln(a);

          write('Nhap chieu rong = '); readln(b);

          writeln('Chu vi hinh chu nhat: ', (a+b)*2);

          writeln('Dien tich hinh chu nhat: ', a*b);

          readln

end.

3.

program btsydn;

uses crt;

  var n: real;

begin

          clrscr;

          write('Nhap n = '); readln(n);

          if n mod 2 = 0 then write(n, ' la so chan') else (n, ' la so le');

          readln

end.