deret aritmatika, u6=17 u10=33,jml 30 suku pertama deret?

b = 4
a = -3
sn= 1/2n(2a+(n-1)b) = 1/2.30(2(-3)+29*4) = 15 (-6+116) = 15*110 = 1650

Dik
U6   = a + 5b = 17
U10 = a + 9b = 33   --
                -4 b = - 16
                     b = 4
a + 5b = 17
a + 5.4 = 17
a = 17 - 20
a = - 3

S 30 = n/2(2a + 29b)
S 30 = 30/2(2.-3 + 29.4)
S 30 = 15(110)
S 30 = 1650



semoga membantu ^_^