Să se calculeze:
a)
[tex] \frac{8!}{7!} + \frac{ 10!}{8!} [/tex]
b)
[tex] \frac{7!}{6!} + \frac{5!}{5!} [/tex]


Răspuns :

8!/7! + 10!/8! = 8·7!/7!+10·9·8!/8!=8+90=98

7!/6! + 5!/5! = 7·6!/6!+1=7+1=8