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anonymous
 5 years ago
There are some binomials that can be expanded directly by a general inspection. For example (x+a)(x+b)=x^2+x(a+b)+ab.
Can you help me to recognize to which case does the following expression belongs to?
(3x+7)(7x3)
anonymous
 5 years ago
There are some binomials that can be expanded directly by a general inspection. For example (x+a)(x+b)=x^2+x(a+b)+ab. Can you help me to recognize to which case does the following expression belongs to? (3x+7)(7x3)

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anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0I found the answer guys :)

radar
 5 years ago
Best ResponseYou've already chosen the best response.0Did you expand it by inspection? Or did you use paper & pencil?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0after a while, FOILing with small numbers becomes easy in the example above, you would do I'm not sure where i learned this from, or maybe i came up with it (i'm definitely not the first to do so!) (ax + b)(cx + d) (a*b)x^2 + (bc + ad)x + bd it's really just a "formula" for FOIL so your example (3x+7)(7x3) (3 * 7)x^2 + (49 + 9)x + 21 21x^2 + 40x  21
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