document.write( "Question 446792: I need help solving this problem:\r
\n" ); document.write( "\n" ); document.write( "1n (x+7) + 1n (x+3) = 1n77 \n" ); document.write( "

Algebra.Com's Answer #307729 by mohammadrezai(14) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"1n+%28x%2B7%29+%2B+1n+%28x%2B3%29+=+1n+77\"$
\n" ); document.write( "First must definition domain:
\n" ); document.write( "X+7>0 and x+3>0 there for domain is x>-3
\n" ); document.write( " $\"1n+%28x%2B7%29+%2B+1n+%28x%2B3+%29+=+ln+%28x%5E2%2B10x%2B21%29=+ln+77\"$
\n" ); document.write( "x^2+10x+21=77
\n" ); document.write( "x^2+10x-56=0
\n" ); document.write( " $\"x+=+%28-10+%2B-+sqrt%28+10%5E2-4%2A1%2A%28-56%29+%29%29%2F%282%2A1%29+\"$
\n" ); document.write( " $\"x1+=+%28-10+-+sqrt%28+324+%29%29%2F+2+\"$
\n" ); document.write( " $\"x1=+%28-10-18%29%2F2=-14\"$ that is not acceptable and
\n" ); document.write( " $\"x2+=+%28-10+%2B+sqrt%28324%29%29%2F+2+\"$
\n" ); document.write( " $\"x2=%28-10%2B18%29%2F2=4\"$ is acceptable and is answer.
\n" ); document.write( "Other solution is
\n" ); document.write( "ln a ln b= ln 77 find a and b that multiple are 77.
\n" ); document.write( "a=7 and b= 11 (or a=11 and b=7)! There for x=4\r
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