Change the base – If 9x = 275, what is x?
Some questions will require changing the base of a number with an exponent. For example,
16x = 2564, then what is x?
256 = 162 , meaning that the original equation can be rewritten as 16x = (162)4 = 168
This will usually involve numbers whose square or cube roots are simple integers.
So it’s useful to get familiar recognizing the first few numbers in these exponent sequences:
Number | x2 | x3 | x4 |
---|---|---|---|
2 | 4 | 8 | 16 |
3 | 9 | 27 | 81 |
4 | 16 | 64 | 256 |
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