document.write( "Question 703877: Please help me solve this:
\n" ); document.write( "\"2x%5E3+-+x%5E2+%3E=+0\" <=> \"x%5E2%2A%282x+-+1%29+%3E=+0\"
\n" ); document.write( "and solutions are: x = 0 or x >= 1/2, because:
\n" ); document.write( "\"2x+-+1+%3E=+0\" <=> \"x+%3E=+1%2F2\"
\n" ); document.write( "\"x%5E2+%3E=+0\" <=> \"x+%3E=+sqrt%280%29\" <=> \"x+%3E=+0\"
\n" ); document.write( "but why x = 0 and not x >= 0?
\n" ); document.write( "

Algebra.Com's Answer #433768 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
AN PICTURE IS WORD A THOUSAND WORDS:
\n" ); document.write( "This is how my 11th grade math teacher taught me how to solve that kind of problem. (Teachers may have tried to teach me some math earlier than that, but I was not paying too much attention).
\n" ); document.write( "The sign of a product:
\n" ); document.write( " You place pluses, minuses, and zeros on the stacked (lined up) number lines for each factor.
\n" ); document.write( "Then, you figure out the pluses, minuses, and zeros of the product and write them on the bottom number line (the one for the product)
\n" ); document.write( "
\n" ); document.write( "GRAPHS:
\n" ); document.write( "\"x%5E2\" \"graph%28300%2C300%2C-1.5%2C1.5%2C-0.5%2C0.5%2Cx%5E2%29\" times \"%282x-1%29\" \"graph%28300%2C300%2C-2%2C2%2C-5%2C5%2C2x-1%29\" equals \"x%5E2%282x-1%29\" \"graph%28300%2C300%2C-1.5%2C1.5%2C-0.5%2C0.5%2Cx%5E2%282x-1%29%29\"
\n" ); document.write( "
\n" ); document.write( "AN EXPLANATION IN MANY WORDS:
\n" ); document.write( "\"x%5E2\" is zero for \"x=0\"
\n" ); document.write( "For all other values of \"x\", \"x%5E2%3E0\" is positive,
\n" ); document.write( "and \"x%5E2%2A%282x+-+1%29+\" will go along with \"%282x-1%29\",
\n" ); document.write( "being negative for all \"x%3C1%2F2\",
\n" ); document.write( "except for \"x=0\", where \"%282x-1%29%3C0\",
\n" ); document.write( "but because \"x%5E2=0\", \"x%5E2%282x-1%29=0\"
\n" ); document.write( "At that point \"x%5E2%282x-1%29\" refuses to go along with \"%282x-1%29\".
\n" ); document.write( "
\n" );