Question

Evaluate the summation of 3 times negative 2 to the n minus 1 power, from n equals 1 to 5.

Answer 1

The answer is C.33

3 * (-2)ⁿ⁻¹
n = 1;  3 * (-2)¹⁻¹ = 3 * (-2)⁰ = 3 * 1 = 3
n = 2;  3 * (-2)²⁻¹ = 3 * (-2)¹ = 3 * (-2) = -6
n = 3;  3 * (-2)³⁻¹ = 3 * (-2)² = 3 * 4 = 12
n = 4;  3 * (-2)⁴⁻¹ = 3 * (-2)³ = 3 * (-8) = -24
n = 5;  3 * (-2)⁵⁻¹ = 3 * (-2)⁴ = 3 * 16 = 48

The sum is:
3 + (-6) + 12 + (-24) + 48 = 3 - 6 + 12 - 24 + 48 = 33