SOLUTION: how do i know if i get the right answer? a lot of times on tests, i don't know if i have the right answer or not, usually on the more difficult questions. here's one question: (

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: how do i know if i get the right answer? a lot of times on tests, i don't know if i have the right answer or not, usually on the more difficult questions. here's one question: (      Log On


   

Question 222848: how do i know if i get the right answer? a lot of times on tests, i don't know if i have the right answer or not, usually on the more difficult questions.
here's one question: (2+3i)+(-4+5i)-(9-3i)/3.
the slash is dividing. the answer is -5-9i i beleive. what i wanna know, is how do you expand this question? how is it solved?
thanks.
Found 2 solutions by jim_thompson5910, stanbon:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
If the expression is %282%2B3i%29%2B%28-4%2B5i%29-%289-3i%29%2F3, then...


%282%2B3i%29%2B%28-4%2B5i%29-%289-3i%29%2F3 Start with the given expression.


%282%2B3i%29%2B%28-4%2B5i%29-%289%2F3-%283i%29%2F3%29 Break up the fraction


%282%2B3i%29%2B%28-4%2B5i%29-%283-i%29 Reduce.


2%2B3i-4%2B5i-3%2Bi Distribute


-5%2B9i Combine like terms.


So %282%2B3i%29%2B%28-4%2B5i%29-%289-3i%29%2F3=-5%2B9i

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
(2+3i)+(-4+5i)-(9-3i)/3
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Assuming that "3" is only dividing (9-3i) you get:
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= (2+3i)+(-4+5i)-(3-i)
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= [2-4-3]+[3i+5i+i]
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= -5 + 9i
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Cheers,
Stan H.
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When you have equations you can check you answer to see if it works.
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When you have a problem like the one you posted you can only
check your own work to see that you did not make a mistake.
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Cheers,
Stan H.