jika u3 =5 dan u7=5/81. maka r=...., a=....,u5=....

Mencari r
U7/U3 = ar^6/ar^2 = 5 : 5/81
= r^4 = 5 × 81/5
= r^4 = 81
= r = 3

Suku awal (a) = ar^2 = 5/81
= a.9 = 5/81
= a = 5/729

U5 = ar^4 = 5/729.81
= 5/9

Coba dicek lagi yaa, maaf kalau salah:(