(2+5i)(3-i)-(3-i)(3+i) please solve math?

Question

(2+5i)(3-i)-(3-i)(3+i) please evaluate that equation. Thanks.

Answer 1

( 6 - 2i + 15i + 5 ) - ( 9 + 1 )
( 11 + 13i ) - 10
1 + 13i

Answer 2

Use the fact that: i² = - 1, expand and simplify

(2 + 5i)(3 - i) - (3 - i)(3 + i) = 6 + 15i - 2i - 5i² - [9 - i²]

= 6 - 9 + 15i - 2i - 5i² + i²

= - 3 + 13i - 4i² = - 3 + 13i + 4 = 13i + 1.

Answer 3

1+13i