mohon bantuannya mastah

Sn = 2n^2 - n
Dit . U5

rumus :
Un = Sn - S(n-1)

U5 = S5 - S4

S5 = 2(5)^2 -5
= 2 × 25 - 5
= 50 - 5 = 45

S4 = 2(4)^2 - 4
= 2 × 16 - 4
= 32 - 4
= 28

U5 = 45 - 28 = 17 (E)