Answer:
a)
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b)
x
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Explanation:
You can group together like base values, so 3 x 3 x 3 x 3 x 3 becomes 3 to the power of 5. All it means is that you are multiplying the base value (in this case 3) by itself 5 times.
Index notation makes it easier in more complex equations to solve, as its simpler and doesn't take up as much space.
Hope this helped : )