document.write( "Question 150829: Hi, please answer this question.
\n" ); document.write( "I have: x^2-x-5=0. I know how to solve this using the quadratic equation method. The answers I get are (1+-sqrt(21))/2.
\n" ); document.write( "But instead of using the quadratic formula, can't I just say:
\n" ); document.write( "x^2-x=5
\n" ); document.write( "x(x-1)=5
\n" ); document.write( "x=5 or x=6
\n" ); document.write( "How come this answer is different from the one using the quadratic formula???
\n" ); document.write( "Thank you. \n" ); document.write( "

Algebra.Com's Answer #110755 by jim_thompson5910(35256) $\"\"$ $\"About$

You can put this solution on YOUR website!
You're thinking of the zero product property. The zero product property says that if $\"AB=0\"$ , then $\"A=0\"$ or $\"B=0\"$ \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "However, if you have $\"A%2AB=C\"$ where in this case $\"C%3C%3E0\"$ , you cannot say that $\"A=C\"$ or $\"B=C\"$ \n" ); document.write( "

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