| Resolviendo |
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Descomponiendo los exponentes, recordar que $n^{a+b}=n^a\cdot n^b$ |
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$N=\dfrac{3^{\textstyle a+2}+3^{\textstyle a+4}}{3^{\textstyle a+3}-4 \cdot 3^{\textstyle a+1}}$ |
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$N=\dfrac{3^a \cdot 3^2 +3^a \cdot 3^4}{3^a \cdot 3^3-4 \cdot 3^a \cdot 3^1}$ |
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Factorizando $3^a$ |
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$N=\dfrac{3^a \cdot (3^2 + 3^4)}{3^a \cdot (3^3-4 \cdot 3^1)}$ |
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Simplificando $3^a$ |
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$N=\dfrac{3^2 + 3^4}{3^3-4 \cdot 3^1}$ |
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$N=\dfrac{9 +81}{27-4 \cdot 3}$ |
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$N=\dfrac{90}{27-12}$ |
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$N=\dfrac{90}{15}$ |
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$N=6$ |
| Respuesta: |
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La solución es la Alternativa B |
