document.write( "Question 120476: What are the roots of the equation x^2+9=0 I got x=+-3i,can someone explain? \n" ); document.write( "

Algebra.Com's Answer #88334 by tutor_paul(519) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"x%5E2%2B9=0\"$
\n" ); document.write( "Get the x^2 term alone:
\n" ); document.write( " $\"x%5E2=-9\"$
\n" ); document.write( "Take the square root of both sides:
\n" ); document.write( " $\"sqrt%28x%5E2%29=sqrt%28-9%29\"$
\n" ); document.write( "Notice now you have to take the square root of a negative number of the right side. You can re-write this as:
\n" ); document.write( " $\"x=sqrt%28-1%2A9%29\"$
\n" ); document.write( " $\"x=sqrt%28-1%29%2Asqrt%289%29\"$
\n" ); document.write( "Note that i is defined as follows:
\n" ); document.write( " $\"i=sqrt%28-1%29\"$
\n" ); document.write( "So you can rewrite it as:
\n" ); document.write( " $\"x=i%2Asqrt%289%29\"$
\n" ); document.write( "the square root of 9 is +/-3. So your final answer is:
\n" ); document.write( "x=+/-3i
\n" ); document.write( "==============
\n" ); document.write( "Good Luck,
\n" ); document.write( "tutor_paul@yahoo.com
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