Question

Simplify:
(3i)(5i)(6+5i)

Answer 1

Explanation:

remember, i = sqrt(-1)

let's go left to right :

(3i)(5i) = 3×sqrt(-1)×5×sqrt(-1) = 3×5×sqrt²(-1) = 15×-1 = -15

-15×(6+5i) = -90 - 75i