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How Do You Add Complex Numbers?
Add (8 + 7i) and (4 + 3i).
Summary
- 'i' is the imaginary unit and represents the square root of -1, so it's NOT a variable
- But even though 'i' is not a variable, we can treat it like one when we add
- 8 and 4 are like terms since they're both just constants
- 7i and 3i are also like terms since they both have a number times 'i'
- Group the like terms together to make addition simpler
- The Associative Property allows us to regroup our terms
- The symbol over -1 is the square root symbol
- 7i+3i = 10i, just like 7x+3x = 10x

Notes
-
- Our complex numbers are (8+7i) and (4+3i)
- 'i' is the imaginary unit and represents the square root of -1, so it's NOT a variable
- But even though 'i' is not a variable, we can treat it like one when we add
- 8 and 4 are like terms since they both consist of one number
- 7i and 3i are also like terms since they both have a number times 'i'
-
- We just determined that 8 and 4 are like terms, and so are 7i and 3i
- 'i' is the imaginary unit and represents the square root of -1, so it's NOT a variable
- But even though 'i' is not a variable, we can treat it like one when we add
- The Associative Property allows us to regroup terms, so we can put like terms together
-
- Like terms can be combined, leaving you with fewer terms to work with!
- 8+4 = 12
- Although 'i' is not a variable, addition works just like it does with variables
- So 7i+3i = 10i, just like 7x+3x = 10x