What you need to know

Things to remember:

  • An exponent, or power, tells us how many times we multiply a number by itself.

What is the value of x if 3^x=81?

Remember, an exponent is telling us that we multiply a number by itself a certain number of times. So, this question is asking us to see how many times we have to multiply 3 by itself to make 81. The easiest way to this is to just build it up.

x=1                     3^1=3

x=2                     3^2=3\times3=9

x=3                     3^3=3\times3\times3=9\times3=27

x=4                     3^4=3\times3\times3\times3=9\times3\times=27\times3=81

So, we can see that x=4!


Example Questions

x=1                     4^1=4


x=2                     4^2=4\times4=16


So, we can see that x=4!



x=1                     5^1=4

x=2                     5^2=5\times5=25


x=3                     5^3=5\times5\times5=25\times5=125




So, we can see that x=4!



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