а) (5+2i)(2-5i) = 10 - 25i + 4i - 10i^2 = 10 - 21i + 10 = 20 - 21i
б) (3+2i)^2 - 2i(1-3i)= (3)^2 + 2(3)(2i) + (2i)^2 - 2i + 6i= 9 + 12i - 4 + 4 - 2i + 6i= 9 - 4 + 4 + 12i - 2i + 6i= 9 + 12i
в) (3-5i)/(1+2i)= (3-5i)(1-2i)/(1+2i)(1-2i)= 3 - 6i - 5i + 10i^2 / (1 + 2i - 2i - 4i^2)= 3 - 11i - 10 / (1 + 4)= -7 - 11i / 5
Г) (2-5i)/(5+2i) - (4+3i)/(3-4i)= [(2-5i)(5-2i) - (4+3i)(3+4i)] / [(5+2i)(5-2i)]= [10 - 4i - 25i + 10i^2 - 12 - 16i + 9i + 12i^2] / [25 - 4i^2]= [10 - 4i - 25i - 10 - 16i + 9i] / 29= (-10 - 46i) / 29= -10/29 - 46i/29
а) (5+2i)(2-5i) = 10 - 25i + 4i - 10i^2 = 10 - 21i + 10 = 20 - 21i
б) (3+2i)^2 - 2i(1-3i)
= (3)^2 + 2(3)(2i) + (2i)^2 - 2i + 6i
= 9 + 12i - 4 + 4 - 2i + 6i
= 9 - 4 + 4 + 12i - 2i + 6i
= 9 + 12i
в) (3-5i)/(1+2i)
= (3-5i)(1-2i)/(1+2i)(1-2i)
= 3 - 6i - 5i + 10i^2 / (1 + 2i - 2i - 4i^2)
= 3 - 11i - 10 / (1 + 4)
= -7 - 11i / 5
Г) (2-5i)/(5+2i) - (4+3i)/(3-4i)
= [(2-5i)(5-2i) - (4+3i)(3+4i)] / [(5+2i)(5-2i)]
= [10 - 4i - 25i + 10i^2 - 12 - 16i + 9i + 12i^2] / [25 - 4i^2]
= [10 - 4i - 25i - 10 - 16i + 9i] / 29
= (-10 - 46i) / 29
= -10/29 - 46i/29