diketahui barisan bilangan 7,13,19,25,... berapakah U10 dan S7

MAPEL = MATEMATIKA
KELAS = 9
BAB = BARISAN & DERET

diketahui =
a = 7
b = 13 - 7 = 6

ditanya = U10 & S7 ??

------- Barisan Aritmatika -------

U10 = a + ( n - 1 )b
U10 = 7 + ( 10 - 1 )(6)
U10 = 7 + 9(6)
U10 = 7 + 54
U10 = 61

S7 = n/2( 2a + ( n - 1 )b )
S7 = 7/2( 2(7) + ( 7 - 1 )(6) )
S7 = 7/2( 14 + 36 )
S7 = 7/2( 50 )
S7 = 7 × 25
S7 = 175

semoga membantu