Respuesta :

ferrybukantoro

Step-by-step explanation:

the value of the 13th coefficient in the expansion of {(a + b)}^{15} :

(13-1)C15 = 12C15 = 15! / 3!. 12!

= 15×14×13×12! / 3×2×12!

= 2730/6

= 455

Otras preguntas