diketahui= a=5,r=2 ditanyakan= a.5 suku pertama barisan geometri b.u8 c.s10

a. S5 = a ( r^n - 1 ) : r - 1
S5 = 5 ( 2^5 - 1 ) : 2 - 1
S5 = 5 ( 32 - 1 ) : 1
S5 = 5 ( 31 )
S5 = 155

b. U8 = ar^7
U8 = (5)(2)^7
U8 = (5)(128)
U8 = 640

c. S10 = a ( r^n - 1 ) : r - 1
S10 = 5 ( 2^10 - 1 ) : 2 - 1
S10 = 5 ( 1024 - 1 ) : 1
S10 = 5 ( 1023 )
S10 = 5115