6+12+24+...+3x2^n = 6(2pangkat n -1)

6+12+24 +...+ 3.2ⁿ = 6. 2ⁿ⁻¹
n= 1 → 6 = 6
n = k → 6+12+24+...+ 3. 2^k = 6. 2^(k-1)
n = k+1
6. 2^(k-1) + 3. 2(^k+1) = 6. 2 ^(k+1-1)
6. 2^-1. 2^k + 3. 2^k . 2 = 6. 2^(k)
6/2 . 2^k + 6. 2^k = 6. 2^k
3 .2^k + 6 . 2^k = 6. 2^k
9 . 2^k = 6 . 2^k
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