document.write( "Question 148296: Solve by the substitution method
\n" ); document.write( "2x + 7 =12
\n" ); document.write( " x = 8 - 4y \n" ); document.write( "
Algebra.Com's Answer #108718 by nerdybill(7384)\"\" \"About 
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2x + 7 =12 <--equation 1
\n" ); document.write( "x = 8 - 4y <--equation 2
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\n" ); document.write( "Notice equation 2 states that'x' is equal to (8 - 4y) -- substitute this into equation 1:
\n" ); document.write( "2x + 7 =12
\n" ); document.write( "2(8 - 4y) + 7 =12
\n" ); document.write( "16 - 8y + 7 =12
\n" ); document.write( "23 - 8y =12
\n" ); document.write( "-8y = -11
\n" ); document.write( "y = 11/8 (solution for y)
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\n" ); document.write( "substitute the above into equation 2 and solve for x:
\n" ); document.write( "x = 8 - 4y
\n" ); document.write( "x = 8 - 4(11/8)
\n" ); document.write( "x = 8 - 11/2
\n" ); document.write( "x = 16/2 - 11/2
\n" ); document.write( "x = 5/2 (solution for x)\r
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