If u⃗=(a,2)\vec{u} = (a, 2)u=(a,2) and v⃗=(4,−3)\vec{v} = (4, -3)v=(4,−3) are perpendicular, find aaa.
32\frac{3}{2}23
−32-\frac{3}{2}−23
666
12\frac{1}{2}21