document.write( "Question 109909: I need some help PLEASE!!!!
\n" ); document.write( "solve each of the following by substitution \r
\n" ); document.write( "\n" ); document.write( "4x-12y=5
\n" ); document.write( "-x+3y=-1\r
\n" ); document.write( "\n" ); document.write( "Thanks
\n" ); document.write( "Heather
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Algebra.Com's Answer #80093 by ptaylor(2198)\"\" \"About 
You can put this solution on YOUR website!
4x-12y=5-------------------------eq1
\n" ); document.write( "-x+3y=-1 -------------------------eq2\r
\n" ); document.write( "\n" ); document.write( "O.K. now we will solve for x in eq2 and substitute the value for x into eq1:\r
\n" ); document.write( "\n" ); document.write( "-x+3y=-1 subtract 3y from both sides\r
\n" ); document.write( "\n" ); document.write( "-x+3y-3y=-1-3y collect like terms\r
\n" ); document.write( "\n" ); document.write( "-x=-1-3y multiply each term by -1\r
\n" ); document.write( "\n" ); document.write( "x=1+3y--------------------Now we will substitute this into eq1 and we get:\r
\n" ); document.write( "\n" ); document.write( "4(1+3y)-12y=5 get rid of parens (distributive law)
\n" ); document.write( "4+12y-12y=5--------------------WHOAA!!!!!!! SOMETHING IS WRONG. THERE'S NO SOLUTION \r
\n" ); document.write( "\n" ); document.write( "Lets put eq1 into slope-intercept form (y=mx+b where m is the slope and b is the y-intercept, remember?)\r
\n" ); document.write( "\n" ); document.write( "4x-12y=5 subtract 4x from both sides\r
\n" ); document.write( "\n" ); document.write( "4x-4x-12y=5-4x collect like terms\r
\n" ); document.write( "\n" ); document.write( "-12y=-4x+5 divide each term by -12
\n" ); document.write( "y=(4/12)x-5/12 or
\n" ); document.write( "y=(1/3)x-5/12 ----------------------eq1 in slope-intercept form
\n" ); document.write( "Slope of eq1 is 1/3\r
\n" ); document.write( "\n" ); document.write( "Now for eq2:\r
\n" ); document.write( "\n" ); document.write( "-x+3y=-1 add x to both sides
\n" ); document.write( "-x+x+3y=-1+x collect like terms
\n" ); document.write( "3y=x-1 divide each term by 3
\n" ); document.write( "y=(1/3)x-1/3----------------------eq2 in slope-intercept\r
\n" ); document.write( "\n" ); document.write( "Slope of eq2 is 1/3\r
\n" ); document.write( "\n" ); document.write( "The two lines are parallel. The equations are inconsistent---there is no solution\r
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\n" ); document.write( "\n" ); document.write( "Hope this helps----ptaylor
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