3+8i - (7+4i) × (2-i)
= 3+8i - (14-7i+8i-4i^2)
= 3+8i - (14-7i+8i+4) [since i^2 = -1]
= 3+8i - 14 + 7i - 8i - 4
= -11 + 7i