document.write( "Question 976117: Solve the system of 2 equations and 2 unknowns using the echelon method.\r
\n" ); document.write( "\n" ); document.write( "-4x - 5y = 15
\n" ); document.write( "-2x + 2y = -6\r
\n" ); document.write( "\n" ); document.write( "(___, ___)\r
\n" ); document.write( "\n" ); document.write( "Thanks. \n" ); document.write( "
Algebra.Com's Answer #598966 by Cromlix(4381)\"\" \"About 
You can put this solution on YOUR website!
Hi there,
\n" ); document.write( "Start with the given system of equations:
\n" ); document.write( "system:
\n" ); document.write( "-4x - 5y = 15
\n" ); document.write( "-2x + 2y = -6
\n" ); document.write( "Now you have to change the 'x' values
\n" ); document.write( "or the 'y' values to equal values, but
\n" ); document.write( "opposite signs.
\n" ); document.write( "Here we will multiply the lower set by -2
\n" ); document.write( "-4x - 5y = 15
\n" ); document.write( "-2x + 2y = -6 (x -2)\r
\n" ); document.write( "\n" ); document.write( "-4x - 5y = 15
\n" ); document.write( "4x - 4y = 12
\n" ); document.write( "Add the left parts of the equation together,
\n" ); document.write( "then the right parts.
\n" ); document.write( "(-4x - 5y) + (4x - 4y) = 15 + 12
\n" ); document.write( "The 'x' values vanish (-4x + 4x = 0)
\n" ); document.write( " -9y = 27
\n" ); document.write( "Divide both sides by -9
\n" ); document.write( " y = -3
\n" ); document.write( "Substitute y = -3 into
\n" ); document.write( "-4x - 5y = 15
\n" ); document.write( "-4x -5(-3) = 15
\n" ); document.write( "-4x = 15 - 15
\n" ); document.write( "-4x = 0
\n" ); document.write( "x = 0
\n" ); document.write( "{0,-3)
\n" ); document.write( "Hope this helps:-)
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