document.write( "Question 58851This question is from textbook Beginning Algebra
\n" ); document.write( ": Could someone be so kind in helping me with this problem?\r
\n" ); document.write( "\n" ); document.write( " I need to solve the following systems by substitution:\r
\n" ); document.write( "\n" ); document.write( " 8x - 4y = 16
\n" ); document.write( " y = 2x - 4\r
\n" ); document.write( "\n" ); document.write( "Thank you so much,
\n" ); document.write( " Ashley \n" ); document.write( "
Algebra.Com's Answer #40359 by funmath(2933)\"\" \"About 
You can put this solution on YOUR website!
Hi Ashley,
\n" ); document.write( "Solve the following systems by substitution:\r
\n" ); document.write( "\n" ); document.write( "L1) 8x - 4y = 16
\n" ); document.write( "L2) y = 2x - 4
\n" ); document.write( "Substitute 2x-4 for y in L2) and solve for x:
\n" ); document.write( "8x-4(2x-4)=16
\n" ); document.write( "8x-8x-16=16
\n" ); document.write( "0+16=16
\n" ); document.write( "16=16
\n" ); document.write( "Your variable was eliminated and 16 = 16, therefore there is an infinite number of solutions. The lines are lying on top of each other, they are graphically the same line and have all points in common.
\n" ); document.write( "Some books list the solution to something with an infinite number of solutions as (x,2x-4). Most are happy with \"all real numbers\" or \"infinite solutions.\"
\n" ); document.write( ":
\n" ); document.write( "Just to prove a point, watch what happens when you try to solve L1 for y:
\n" ); document.write( "8x-4y=16
\n" ); document.write( "-8x+8x-4y=-8x+16
\n" ); document.write( "-4y=-8x+16
\n" ); document.write( "-4y/-4=-8x/-4+16/-4
\n" ); document.write( "y=2x-4 It turns right into L2!
\n" ); document.write( "Happy Calculating!!!
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