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You can put this solution on YOUR website!
log(6*5^x-25*20^x)=x+log(25)
\n" ); document.write( "..
\n" ); document.write( "log(6*5^x-25*20^x)-log(25)=x
\n" ); document.write( "=log{(6*5^x-25*20^x)/25}=x
\n" ); document.write( "change to exponential form\r
\n" ); document.write( "\n" ); document.write( "10^x={(6*5^x-25*20^x)/25}
\n" ); document.write( "(2^x*5^x)=((6*5^x)-25(4^x*5^x))/25
\n" ); document.write( "divide by 5^x
\n" ); document.write( "2^x=(6-25*4^x)/25
\n" ); document.write( "25*2^x=6-25*4^x
\n" ); document.write( "25*4^x+25*2^x=6
\n" ); document.write( "25*4^x+25*2^x-6=0
\n" ); document.write( "4^x=2^2x
\n" ); document.write( "let u=2^x
\n" ); document.write( "then u^2=2^2x
\n" ); document.write( "you then have a quadratic equation to solve
\n" ); document.write( "25u^2+25u-6=0
\n" ); document.write( "(5u+6)(5u-1)=0
\n" ); document.write( "5u+6=0
\n" ); document.write( "u=-6/5 (reject, no solution}
\n" ); document.write( "5u-1=0
\n" ); document.write( "u=1/5
\n" ); document.write( "u=2^x
\n" ); document.write( "2^x=1/5=.2
\n" ); document.write( "xlog2=log(.2)
\n" ); document.write( "x=(log(.2))/log2
\n" ); document.write( "from calculator
\n" ); document.write( "ans: x=-2.322\r
\n" ); document.write( "\n" ); document.write( "..
\n" ); document.write( "Check:
\n" ); document.write( "x+log25=-2.322+1.398=-.924
\n" ); document.write( "6*5^x=6*5^-2.322=.143
\n" ); document.write( "25*20^x=25*20^-2.322=.024
\n" ); document.write( "log(.143-.024)=log(.119)=-.924\r
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