Tolong jawab ya.. Thx

f(x)= k × 2^(x-2)
3 = k × 2^(2-2)
3 = k × 2^0
3=k×1
k=3

f(x)=3× 2^(x-2)
f(4)=3× 2^(4-2)
f(4)=3× 2² = 3×4=12