C-04-Q234mediumsingle_mcq3⋅2n+1−4⋅2n−12n+2=?\dfrac{3 \cdot 2^{n+1} - 4 \cdot 2^{n-1}}{2^{n+2}} = ?2n+23⋅2n+1−4⋅2n−1=?a12\dfrac{1}{2}21b54\dfrac{5}{4}4