help please Finding the domain
\[9-7\log_{2} \ (\frac{ x }{ 7 }-6)\]
You cannot take the log of a number less than or equal to 0. So log(A) is defined only for A > 0. You can use that to find the domain.
so would it be \[(\frac{ 6 }{ 7 }-\infty)\]
No. When taking the log of (x/7 - 6) we have to make sure (x/7 - 6) > 0 Solve the inequality: (x/7 - 6) > 0
\[x >42\]
Yes. All values of x > 42 is fine. How would you express that in interval form?
\[(42,\infty)\]
Yes. That is it!
thank you so much
you are welcome.
one more question could i approach this problem \[e^{x ^{2}}= e ^{16x}*\frac{ 1 }{ e ^{60} }\]
how^
\[\Large e^{x ^{2}}= e ^{16x}*\frac{ 1 }{ e ^{60} }\] Take natural log on both sides and solve for x.
\[\Large \log(a)^m = m * \log(a)\]
\[\Large \log(A*B) = \log(A) + \log(B)\] \[\Large \frac{ 1 }{ a^m } = a^{-m}\]
\[x ^{2}=x*\log_{16} * e ^{-60}\]
?
\[\Large \ln(e^{x ^{2}})= \ln(e ^{16x}*\frac{ 1 }{ e ^{60} }) = \ln(e ^{16x}) + \ln(\frac{ 1 }{ e ^{60} })\]
\[\Large x^2 = 16x + \ln(e^{-60}) = 16x - 60\]
so in there I can use as \[x ^{2}-16x+60= (x-10)(x-6)= answers would be X=6,10\]
Yes.
thanks
yw.
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