Возвести в степень (-15+8i)^4
= (-15)⁴ + 4*(-15)³*8i + 6*(-15)²*(8i)² + 4*(-15)*(8i)³ + (8i)⁴ = = 50625 - 108000i - 86400 + 30720i + 4096 = = - 31679 - 77280i