Difference between revisions of "FOIL"
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<cmath>(a+b)(c+d) = ac + ad + bc + bd</cmath> | <cmath>(a+b)(c+d) = ac + ad + bc + bd</cmath> | ||
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+ | Here is an example. | ||
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+ | <cmath>(5x + 3)(2x - 6)</cmath> | ||
+ | |||
+ | First we multiply the first terms <cmath>5x \times 2x = 10x^2</cmath> | ||
+ | |||
+ | Then, the outside terms <cmath>5x \times -6 = -30x</cmath> | ||
+ | |||
+ | Next, the inside terms <cmath>3 \times 2x = 6x</cmath>. | ||
+ | |||
+ | Finally, we multiply the last terms <cmath>-6 \times 3 = -18</cmath> | ||
+ | |||
+ | Thus, our answer is <cmath>10x^2 - 30x + 6x - 18</cmath>, which, when simplified, gives us a final answer of <cmath>\boxed{10x^2 - 24x - 18}</cmath>. | ||
== See also == | == See also == | ||
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*[[Simon's Favorite Factoring Trick]] | *[[Simon's Favorite Factoring Trick]] | ||
− | [[Category: | + | [[Category:Algebra]] |
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Latest revision as of 13:34, 14 July 2021
FOIL, standing for first, outside, inside, last, is a mnemonic device for remembering the distributive property when two binomials are multiplied.
Here is an example.
First we multiply the first terms
Then, the outside terms
Next, the inside terms .
Finally, we multiply the last terms
Thus, our answer is , which, when simplified, gives us a final answer of
.