SOLUTION: Multiply and simplify: (5 − 2i)(4 + 7i). Write the answer in the form a + bi, where a and b are real numbers. I used FOIL and got the answer: (-14i^2)+27i+20 but ev

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Question 891710: Multiply and simplify: (5 − 2i)(4 + 7i).
Write the answer in the form a + bi, where a and b are real numbers.


I used FOIL and got the answer: (-14i^2)+27i+20
but every online calculator is telling me the answer is 34+27i
What is the correct answer?
Found 2 solutions by Tatiana_Stebko, MathTherapy:
Answer by Tatiana_Stebko(1539)   (Show Source): You can put this solution on YOUR website!

Use FOIL

since

Answer:
Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!
Multiply and simplify: (5 − 2i)(4 + 7i).
Write the answer in the form a + bi, where a and b are real numbers.


I used FOIL and got the answer: (-14i^2)+27i+20
but every online calculator is telling me the answer is 34+27i
What is the correct answer?


, so substituting - 1 for  in  results in , or 

14 + 27i + 20, which simplifies to: , the same answer you've been getting. 

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