SOLUTION: Simplify each expression. 1.sqrt -81 2.(5-2i)(2+5i) 3.3+5i/2-4i

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Question 433387: Simplify each expression.
1.sqrt -81
2.(5-2i)(2+5i)
3.3+5i/2-4i
Found 2 solutions by Gogonati, robertb:
Answer by Gogonati(855) About Me  (Show Source):
You can put this solution on YOUR website!
1. .
2.%285-2i%29%2A%282%2B5i%29=10%2B25i-4i-10i%5E2=20%2B21%2Ai.
3..
Done.

Answer by robertb(5830) About Me  (Show Source):