J janekela New member Joined Jan 15, 2006 Messages 5 Jan 15, 2006 #1 hi well i got some homework recently but i just cant get it correct 4^x(5^2x)=10 any help at all would be appreciated
hi well i got some homework recently but i just cant get it correct 4^x(5^2x)=10 any help at all would be appreciated
C ChaoticLlama Junior Member Joined Dec 11, 2004 Messages 199 Jan 15, 2006 #2 First step is to take the log of both side. Then use the property of logs such that: log(a*b) = log(a) + log(b) and log(x^y) = ylog(x) you should end up with x = 1/2
First step is to take the log of both side. Then use the property of logs such that: log(a*b) = log(a) + log(b) and log(x^y) = ylog(x) you should end up with x = 1/2
S soroban Elite Member Joined Jan 28, 2005 Messages 5,584 Jan 15, 2006 #3 Hello, janekela! We don't need logs . . . We have: \(\displaystyle \4^x)\cdot(5^{2x})\;=\;10\) The left side is: \(\displaystyle \:[(2^2)^x]\cdot(5^{2x})\;=\;(2^{2x})(5^{2x})\;=\;(2\cdot5)^{2x}\;=\;10^{2x}\) The equation becomes: \(\displaystyle \:10^{2x}\;=\;10^1\) Therefore: \(\displaystyle \;2x\,=\,1\;\;\Rightarrow\;\;x\,=\,\frac{1}{2}\)
Hello, janekela! We don't need logs . . . We have: \(\displaystyle \4^x)\cdot(5^{2x})\;=\;10\) The left side is: \(\displaystyle \:[(2^2)^x]\cdot(5^{2x})\;=\;(2^{2x})(5^{2x})\;=\;(2\cdot5)^{2x}\;=\;10^{2x}\) The equation becomes: \(\displaystyle \:10^{2x}\;=\;10^1\) Therefore: \(\displaystyle \;2x\,=\,1\;\;\Rightarrow\;\;x\,=\,\frac{1}{2}\)