How do you solve #7^(2-10r)+1=46#?

1 Answer
Annie
Aug 20, 2016

4.376x# 10^-3#

Explanation:

#7^(2-10r)# +1=46
So #7^(2-10r)# =45

Remember #2^3# =8 is the same thing #log_2#8 =3

So I can write the equation as :

#log_7#45 =2-10r
Rearranging gives us 10r=2-#log_7#45

10r =0.04376..
r=4.376x #10^-3#

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