SOLUTION: Expand Q1 (a-3b)2

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Question 147513: Expand
Q1 (a-3b)2


Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

%28a-3b%29%5E2+ Start with the given expression.


%28a-3b%29%28a-3b%29 Expand. Remember something like x%5E2=x%2Ax.


Now let's FOIL the expression.


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


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


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


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


%28a%2Bhighlight%28-3b%29%29%28a%2Bhighlight%28-3b%29%29 Multiply the Last terms:%28-3%2Ab%29%2A%28-3%2Ab%29=9%2Ab%5E2.


a%5E2-3%2Aa%2Ab-3%2Aa%2Ab%2B9%2Ab%5E2 Now collect every term to make a single expression.


a%5E2-6%2Aa%2Ab%2B9%2Ab%5E2 Now combine like terms.


So %28a-3b%29%5E2+ FOILS to a%5E2-6%2Aa%2Ab%2B9%2Ab%5E2.


In other words, %28a-3b%29%5E2+=a%5E2-6%2Aa%2Ab%2B9%2Ab%5E2.