document.write( "Question 819671: How do you multiply expressions, using variables, within a set of parentheses?
\n" ); document.write( "the problem I'm working on:\r
\n" ); document.write( "\n" ); document.write( "(X+3) (4x+5)\r
\n" ); document.write( "\n" ); document.write( "sorry if this is a super obvious one, I'm still in Algebra 1. :P \n" ); document.write( "
Algebra.Com's Answer #496617 by richwmiller(17219)\"\" \"About 
You can put this solution on YOUR website!
Be careful X is not the same as x.
\n" ); document.write( "(X+3) (4x+5)
\n" ); document.write( "I will assume you really meant
\n" ); document.write( "(x+3) (4x+5)
\n" ); document.write( "The method is called FOIL.
\n" ); document.write( "First x+4x which equals 4x^2
\n" ); document.write( "outer x*5
\n" ); document.write( "inner 3*4x
\n" ); document.write( "last 3*5
\n" ); document.write( "add them
\n" ); document.write( "4x^2+5x+12x_+15
\n" ); document.write( "4x^2+17x+15
\n" ); document.write( "We are finished.\r
\n" ); document.write( "\n" ); document.write( "but to work backwards
\n" ); document.write( "we want factors of 60 (4*15) which add up to 17
\n" ); document.write( "5*12=60 5+12=17
\n" ); document.write( "4x^2+5x+12x_+15\r
\n" ); document.write( "\n" ); document.write( "4x^2+12x+5x+15
\n" ); document.write( "4x*(x+3)+5*(x+3)
\n" ); document.write( "(4x+5)*(x+3)
\n" ); document.write( "and we are back where we started.\r
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