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Without calculator, I have to determine which of the following is larger:

$2^{350}$ or $5^{150}$

I know only very basic exponential laws, and haven't covered logarithms yet. Tried various algebraic simplification methods but had no luck.

Any help is much appreciated, thanks in advance.

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3 Answers

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Hint

This should help:

$$2^7=128>125=5^3$$

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To evaluate these values, they must be placed on the same “platform”.

Find $x$ such that $2^{350} = (x)^{50}$. Similarly, find $y$ such that $5^{150} = (y)^{50}$.

These two numbers are now raised to the same platform and therefore can be compared (now).

If $x > y$ then..., otherwise ......

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The greatest common divisor between $350$ and $150$ is $50$ and we have

$350 = 7 \cdot 50$

and

$150 = 3 \cdot 50$

There's an exponent power rule that states $a^{x \cdot y} = (a^x)^y$

Thus you're comparing

$2^{7 \cdot 50}$ or $(2^7)^{50}$ or $128^{50}$

and

$5^{3 \cdot 50}$ or $(5^3)^{50}$ or $75^{50}$

Since $128 > 75$, then $128^{50} > 75^{50}$

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