SOLUTION: Square the binomial (7x-9)^2

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Question 642610: Square the binomial
(7x-9)^2

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

%287x-9%29%5E2 Start with the given expression.


%287x-9%29%287x-9%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%287x%29-9%29%28highlight%287x%29-9%29 Multiply the First terms:%287%2Ax%29%2A%287%2Ax%29=49%2Ax%5E2.


%28highlight%287x%29-9%29%287x%2Bhighlight%28-9%29%29 Multiply the Outer terms:%287%2Ax%29%2A%28-9%29=-63%2Ax.


%287x%2Bhighlight%28-9%29%29%28highlight%287x%29-9%29 Multiply the Inner terms:%28-9%29%2A%287%2Ax%29=-63%2Ax.


%287x%2Bhighlight%28-9%29%29%287x%2Bhighlight%28-9%29%29 Multiply the Last terms:%28-9%29%2A%28-9%29=81.


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So we have the terms: 49%2Ax%5E2, -63%2Ax, -63%2Ax, 81


49%2Ax%5E2-63%2Ax-63%2Ax%2B81 Now add every term listed above to make a single expression.


49x%5E2-126x%2B81 Now combine like terms.


So %287x-9%29%5E2 FOILs to 49x%5E2-126x%2B81.


In other words, %287x-9%29%5E2=49x%5E2-126x%2B81 for all values of x.

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Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Square the binomial
(7x-9)^2
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= (7x-9)(7x-9)
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= 49x^2 -63x -63x + 81
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= 49x^2 -126x + 81
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Cheers,
Stan H.
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