SOLUTION: Multiply and simplify: (4 + 3i)(9 + 7i). Write the answer in the form a + bi, where a and b are real numbers.

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Question 1040495: Multiply and simplify: (4 + 3i)(9 + 7i).
Write the answer in the form a + bi, where a and b are real numbers.
Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
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Multiply and simplify: (4 + 3i)(9 + 7i).
Write the answer in the form a + bi, where a and b are real numbers.
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Read attentively my answer: 

(4 + 3i)(9 + 7i) = 4*9 + 4*(7i) + (3i)*9 + (3i)*(7i) = 

                   36  +  28i   +  27i   +   21*i^2  =    ( now recall that i%5E2 = -1 and replace i%5E2 by (-1) )

                   36     +   55i        +   21*(-1) =

                   36     +   55i        -   21      =

                   (36-21) +  55i                    =

                    15     +   55i.

Answer.      15 + 55i.