SOLUTION: I need to expand this quadratic equation: (3r+8)^2 I answered 3r^2-+2(8*3)+64 ,but it was counted wrong. Could anyone help me?

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Question 550665: I need to expand this quadratic equation:
(3r+8)^2
I answered 3r^2-+2(8*3)+64 ,but it was counted wrong.
Could anyone help me?

Found 2 solutions by jim_thompson5910, josmiceli:
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!

Start with the given expression.


Expand. Remember something like .


Now let's FOIL the expression.


Remember, when you FOIL an expression, you follow this procedure:


Multiply the First terms:.


Multiply the Outer terms:.


Multiply the Inner terms:.


Multiply the Last terms:.


---------------------------------------------------
So we have the terms: , , ,


Now add every term listed above to make a single expression.


Now combine like terms.


So FOILs to .


In other words, .

Answer by josmiceli(19441)   (Show Source): You can put this solution on YOUR website!


answer
----------------------
There's a very simple way to check this
Pick a small prime number like 13
and say


and


OK

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