Jawabanmu

2014-08-15T18:21:22+07:00
A = -100
b = 1
Un = a + (n-1)b
50 = -100 + (n-1)1
50 = -101 + n
n = 151

S₁₅₁ = 151/2 (-100 + 50)
        = 151/2 (-50)
        = 151 (-25)
        = -3775