¿Cuantas contraseñas de cuatro digitos pueden crearse con los números 1,2,3,4,5,6,7 sin repetirse ningún número?​

8p+(-9)

(-9)3p+5p and you can swith em around

ask i dont know either ; (

step-by-step explanation:

answers

\3. yes the presentation (i.e. odd numbers being written as differences of two squares) is possible for all odd natural number however the presentation may not be unique. for example,  57=112−82=292−28257=112−82=292−282.

\4. 2 can't be written as a difference of two squares because 4-1=3 and 1-1=0 and the difference of squares grows to integers larger that 3.

can i get some in proving questions 1 and 2?