You can put this solution on YOUR website! "Solve the equation."
"log"_7 1/49 = x
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The "'s don't contribute anything.
Solve for x, right?
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1st approach is to recognize that 49 = 7^2, so 1/49 = 7^-2
--> x = -2
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Or use the base change formula.
x = log(1/49)/log(7)
x = -2
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The base change formula always works.
If it were you couldn't use the 1st method.