document.write( "Question 73433: I don't know how to write out the problem, but I'll try my best so you can understand it. The problem I have is -3 square root of 20 times square root of 15. The answer I came to was -30 square root of 3. Is this correct? \n" ); document.write( "

Algebra.Com's Answer #52550 by bucky(2189) $\"\"$ $\"About$

You can put this solution on YOUR website!
Here's how I understood what you said ... your problem is:
\n" ); document.write( ".
\n" ); document.write( " $\"%28-3%29%2Asqrt%2820%29%2Asqrt%2815%29\"$
\n" ); document.write( ".
\n" ); document.write( "and you need to simplify it.
\n" ); document.write( ".
\n" ); document.write( "Congratulations, your answer is correct! You can check your work and see if you did it
\n" ); document.write( "like I did.
\n" ); document.write( ".
\n" ); document.write( "Here's how I did it:
\n" ); document.write( ".
\n" ); document.write( "Notice that 20 can be factored into 4 times 5 and 15 can be factored into 3 times 5.
\n" ); document.write( ".
\n" ); document.write( "Substitute these values into the problem statement to get:
\n" ); document.write( ".
\n" ); document.write( " $\"%28-3%29%2Asqrt%284%2A5%29%2A+sqrt%283%2A5%29\"$
\n" ); document.write( ".
\n" ); document.write( "Now, using the rule that $\"sqrt%28a%2Ab%29+=+sqrt%28a%29%2A+sqrt%28b%29\"$ :
\n" ); document.write( ".
\n" ); document.write( "

\n" ); document.write( ".
\n" ); document.write( "Notice that $\"sqrt%284%29+=+2\"$ and that $\"sqrt%285%29%2Asqrt%285%29+=+5\"$ . We can make these
\n" ); document.write( "substitutions to get:
\n" ); document.write( ".
\n" ); document.write( " $\"%28-3%29%2A2%2A5%2Asqrt%283%29\"$
\n" ); document.write( ".
\n" ); document.write( "Multiplying out the leading constants ((-3)*2*5) = -30 and the answer becomes:
\n" ); document.write( ".
\n" ); document.write( " $\"%28-30%29%2Asqrt%283%29\"$
\n" ); document.write( ".
\n" ); document.write( "Good job! Keep up the good work! \n" ); document.write( "

\n" );