Question

messed up on the last one >_<
it was supposed to be 7 -x = 21 but with the -x little and up high if that makes any sense

Answer 1

\[\large{7^{-x}}=21?\]

Answer 2

yeah it looks like that lalaly

Answer 3

\[\Large 7^{-x} = 21\]


Convert the equation to logarithmic form to get

\[\Large \log_{7}(21)=-x\]


\[\Large -x=\log_{7}(21)\]


Now multiply both sides by -1 to isolate x


\[\Large x=-\log_{7}(21)\]

Answer 4

if you do this with a calculator, they do not have a log base 7. If you used log (base 10), which calculators do have:
log(7^-x)= log(21)
-x log(7)= log(21)
x = - log(21)/log(7)