SOLUTION: what is the product of this expression (a-3b)(2a+2b)

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Question 388671: what is the product of this expression
(a-3b)(2a+2b)
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

%28a-3b%29%282a%2B2b%29 Start with the given expression.


Now let's FOIL the expression.


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


%28highlight%28a%29-3b%29%28highlight%282a%29%2B2b%29 Multiply the First terms:%28a%29%2A%282%2Aa%29=2%2Aa%5E2.


%28highlight%28a%29-3b%29%282a%2Bhighlight%282b%29%29 Multiply the Outer terms:%28a%29%2A%282%2Ab%29=2%2Aa%2Ab.


%28a%2Bhighlight%28-3b%29%29%28highlight%282a%29%2B2b%29 Multiply the Inner terms:%28-3%2Ab%29%2A%282%2Aa%29=-6%2Aa%2Ab.


%28a%2Bhighlight%28-3b%29%29%282a%2Bhighlight%282b%29%29 Multiply the Last terms:%28-3%2Ab%29%2A%282%2Ab%29=-6%2Ab%5E2.


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So we have the terms: 2%2Aa%5E2, 2%2Aa%2Ab, -6%2Aa%2Ab, -6%2Ab%5E2


2%2Aa%5E2%2B2%2Aa%2Ab-6%2Aa%2Ab-6%2Ab%5E2 Now add every term listed above to make a single expression.


2%2Aa%5E2-4%2Aa%2Ab-6%2Ab%5E2 Now combine like terms.


So %28a-3b%29%282a%2B2b%29 FOILs to 2%2Aa%5E2-4%2Aa%2Ab-6%2Ab%5E2.


In other words, %28a-3b%29%282a%2B2b%29=2%2Aa%5E2-4%2Aa%2Ab-6%2Ab%5E2.


If you need more help, email me at jim_thompson5910@hotmail.com

Also, feel free to check out my tutoring website

Jim