Question

ajutor la 15 va roggggggggg​

Answer 1

Răspuns:

6! -inseamna 6 factorial, adica inmultesti toate numerele de la 1 pana la 6

5! - inmultesti toate numerele de la 1 la 5

6!x12-5!x12= 1x2x3x4x5x6x13-1x2x3x4x5x12Acum dai factor comun 1x2x3x4x5=120 si vei scrie 

(1x2x3x4x5) (6x13-12)=120(78-12)=120x66=7920

b) 6!-1!-2!-3!-4!= 1x2x3x4x5x6-1-1x2-1x2x3-1x2x3x4=720-1-2-6-24=687

c) 7!-6!+5!-4!=1x2x3x4x5x6x7-1x2x3x4x5x6+1x2x3x4x5-1x2x3x4= 

1x2x3x4x5x6 (7-1)+1x2x3x4 (5-1)=

720x6+24x4=4320-96= 4224