document.write( "Question 543047: 3+√z-10=√z+5\r
\n" ); document.write( "\n" ); document.write( "I need help solving radical equations please
\n" ); document.write( "

Algebra.Com's Answer #354739 by bucky(2189)\"\" \"About 
You can put this solution on YOUR website!
Given to solve:
\n" ); document.write( ".
\n" ); document.write( "\"3+%2B+sqrt%28z-10%29+=+sqrt%28z%2B5%29\"
\n" ); document.write( ".
\n" ); document.write( "Square both sides. For the left side this involves multiplying:
\n" ); document.write( ".
\n" ); document.write( "\"%283+%2B+sqrt%28z-10%29%29%2A%283+%2B+sqrt%28z-10%29%29\"
\n" ); document.write( ".
\n" ); document.write( "and you can do this by the FOIL process to get:
\n" ); document.write( ".
\n" ); document.write( "\"3%5E2+%2B+3%2Asqrt%28z-10%29+%2B+3%2Asqrt%28z-10%29+%2B+%28sqrt%28z+-+10%29%29%5E2\"
\n" ); document.write( ".
\n" ); document.write( "To simplify this, note that \"3%5E2+=+9\".
\n" ); document.write( ".
\n" ); document.write( "Also note that \"3%2Asqrt%28z-10%29+%2B+3%2Asqrt%28z-10%29+=+6%2Asqrt%28z-10%29\"
\n" ); document.write( ".
\n" ); document.write( "And finally note that \"%28sqrt%28z+-+10%29%29%5E2+=+z+-+10\"
\n" ); document.write( ".
\n" ); document.write( "Make these changes and the squared left side becomes:
\n" ); document.write( ".
\n" ); document.write( "\"9+%2B+6%2Asqrt%28z-10%29+%2B+z+-+10\"
\n" ); document.write( ".
\n" ); document.write( "Squaring the right side results in: \"%28sqrt%28z%2B5%29%29%5E2+=+z+%2B+5\"
\n" ); document.write( ".
\n" ); document.write( "So when both sides of this equation are squared the result is:
\n" ); document.write( ".
\n" ); document.write( "\"9+%2B+6%2Asqrt%28z-10%29+%2B+z+-+10+=+z+%2B+5\"
\n" ); document.write( ".
\n" ); document.write( "Note that you have a +z on the left side and a +z on the right side. Subtracting z from both sides eliminates these two terms and you are left with:
\n" ); document.write( ".
\n" ); document.write( "\"9+%2B+6%2Asqrt%28z-10%29+-+10+=++5\"
\n" ); document.write( ".
\n" ); document.write( "Combine the 9 and the -10 on the left side and you have:
\n" ); document.write( ".
\n" ); document.write( "\"6%2Asqrt%28z-10%29+-+1+=+5\"
\n" ); document.write( ".
\n" ); document.write( "Get rid of the -1 on the left side by adding +1 to both sides to get:
\n" ); document.write( ".
\n" ); document.write( "\"6%2Asqrt%28z-10%29+=+6\"
\n" ); document.write( ".
\n" ); document.write( "Divide both sides by 6 and the equation is then:
\n" ); document.write( ".
\n" ); document.write( "\"sqrt%28z-10%29+=+1\"
\n" ); document.write( ".
\n" ); document.write( "Now square both sides and you have:
\n" ); document.write( ".
\n" ); document.write( "\"z+-+10+=+1\"
\n" ); document.write( ".
\n" ); document.write( "Finally eliminate the -10 on the left side by adding 10 to both sides and the answer you are looking for becomes:
\n" ); document.write( ".
\n" ); document.write( "\"z+=+11\"
\n" ); document.write( ".
\n" ); document.write( "You can check this out by returning to the original equation:
\n" ); document.write( ".
\n" ); document.write( "\"3+%2B+sqrt%28z-10%29+=+sqrt%28z%2B5%29\"
\n" ); document.write( ".
\n" ); document.write( "and substituting 11 for z to get:
\n" ); document.write( ".
\n" ); document.write( "\"3+%2B+sqrt%2811-10%29+=+sqrt%2811%2B5%29\"
\n" ); document.write( ".
\n" ); document.write( "This simplifies to:
\n" ); document.write( ".
\n" ); document.write( "\"3+%2B+sqrt%281%29+=+sqrt%2816%29\"
\n" ); document.write( ".
\n" ); document.write( "and taking the square roots results in:
\n" ); document.write( ".
\n" ); document.write( "\"3+%2B+1+=+4\"
\n" ); document.write( ".
\n" ); document.write( "This is obviously true, so the answer z = 11 checks.
\n" ); document.write( ".
\n" ); document.write( "Hope this helps you to understand the problem.
\n" ); document.write( ".
\n" ); document.write( "
\n" ); document.write( "
\n" );