Difference between revisions of "1978 AHSME Problems/Problem 20"
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The second solution gives us <math>a=b=c</math>, and <math>x=\frac{8a^3}{a^3}=8</math>, which is not negative, so this solution doesn't work. | The second solution gives us <math>a=b=c</math>, and <math>x=\frac{8a^3}{a^3}=8</math>, which is not negative, so this solution doesn't work. | ||
− | Therefore, <math>x=1\Rightarrow\boxed{A}</math>. | + | Therefore, <math>x=-1\Rightarrow\boxed{A}</math>. |
== See also == | == See also == |
Revision as of 22:56, 27 February 2017
If are non-zero real numbers such that
,
and
, and
, then
equals
Solution
Take the first two expressions (you can actually take any two expressions): .
OR
The first solution gives us .
The second solution gives us , and
, which is not negative, so this solution doesn't work.
Therefore, .
See also
1978 AHSME (Problems • Answer Key • Resources) | ||
Preceded by Problem 19 |
Followed by Problem 21 | |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 • 26 • 27 • 28 • 29 • 30 | ||
All AHSME Problems and Solutions |
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