document.write( "Question 582095: I need help factoring. I just don't get it.\r
\n" ); document.write( "\n" ); document.write( "8x^2y+34xy-84y
\n" ); document.write( "

Algebra.Com's Answer #372004 by richard1234(7193)\"\" \"About 
You can put this solution on YOUR website!
First you can factor out 2y:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The 4x^2 + 17x - 42 is a bit tricky to factor; the best way to learn is by experience and simply being able to \"see\" the correct factorization.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "4x^2 + 17x - 42 can be factored into a product (ax + b)(cx + d). We want ac = 4, so a,c can equal 2 or 1,4. However, if a = c = +/- 2, the x coefficient will be even, so try a=1, c=4. We can kind of \"guess and check\" based on the factorization of -42 to obtain the factorization\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( ", in which the complete answer would be .\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Again, this takes lots of practice. Another way you could factor it is to find the roots of 4x^2 + 17x - 42 by the quadratic formula:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Then you could factor it as . However, the leading coefficient is 4 so we can multiply the first term by 4.
\n" ); document.write( "
\n" );