document.write( "Question 900834: I am suppose to solve the systems of equations by elimination and I don't understand it. Here is my problem. It says to solve by substitution.
\n" ); document.write( "x-4y=22
\n" ); document.write( "2x+5y=-21 \n" ); document.write( "

Algebra.Com's Answer #546180 by Jc0110(165) $\"\"$ $\"About$

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$\"x-4y=22\"$ --> Equation 1
\n" ); document.write( " $\"x=22%2B4y\"$ --> Equation 2 ... Substitute into Equation 3.
\n" ); document.write( " $\"2x%2B5y=-21\"$ --> Equation 3
\n" ); document.write( " $\"2%2822%2B4y%29%2B5y=-21\"$
\n" ); document.write( " $\"%2844%2B8y%29%2B5y=-21\"$
\n" ); document.write( " $\"44%2B8y%2B5y=-21\"$
\n" ); document.write( " $\"44%2B13y=-21\"$
\n" ); document.write( " $\"13y=-21-44\"$
\n" ); document.write( " $\"13y=-65\"$
\n" ); document.write( " $\"y=-65%2F13\"$
\n" ); document.write( " $\"y=-5\"$ ... Substitute into Equation 2.
\n" ); document.write( " $\"x=22%2B4%28-5%29\"$
\n" ); document.write( " $\"x=22-20\"$
\n" ); document.write( " $\"x=2\"$
\n" ); document.write( "Therefore, x=2 whereby y=-5. \n" ); document.write( "

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