Respuesta :

Answer:

Step-by-step explanation:

hello :

the sum is : Sn = n/2(U1 + Un )     and U n = U1+(n-1)r    

given :    U1 = 1      r=4-1=7-4=...= 3      n= 32

so :  U 32 = 1+(32-1)3= 94

S32 = 32/2 (1+94) = 1520