document.write( "Question 75916This question is from textbook Prentice Hall Algebra
\n" ); document.write( ": How do you solve \"y=3x+%2B+1\" \"+x=3y+%2B+1\". Using substitution. Our teacher has given us this practice with no review from her. I don't know where to start using substitution. \n" ); document.write( "
Algebra.Com's Answer #54498 by ankor@dixie-net.com(22740)\"\" \"About 
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How do you solve y = 3x + 1: x = 3y + 1. Using substitution.
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\n" ); document.write( "y = (3x+1); than means that where you see \"y\" in the 2nd equation you can
\n" ); document.write( "substitute (3x+1) for y
\n" ); document.write( ":
\n" ); document.write( "The 2nd equation:
\n" ); document.write( "x = 3y + 1
\n" ); document.write( ":
\n" ); document.write( "Now substitute (3x+1) for y in the above equation:
\n" ); document.write( "x = 3(3x+1) + 1
\n" ); document.write( ":
\n" ); document.write( "Multiply what's inside the brackets and you have:
\n" ); document.write( "x = 9x + 3 + 1
\n" ); document.write( "x = 9x + 4
\n" ); document.write( ":
\n" ); document.write( "Subtract x from both sides, subtract 4 from both sides and you have:
\n" ); document.write( "-4 = 9x - x
\n" ); document.write( "-4 = 8x
\n" ); document.write( "x = -4/8
\n" ); document.write( "x = -1/2
\n" ); document.write( ":
\n" ); document.write( "Remember that y = (3x+1)
\n" ); document.write( "x = -1/2 so substitute -1/2 for x:
\n" ); document.write( "y = 3(-1/2) + 1
\n" ); document.write( "y = -3/2 + 1
\n" ); document.write( "y = -3/2 + 2/2
\n" ); document.write( "y = -1/2 also
\n" ); document.write( ":
\n" ); document.write( "Check our solutions by substituting for both x and y in the 2nd equation:
\n" ); document.write( "x = 3y + 1.
\n" ); document.write( "-1/2 = 3(-1/2) + 1
\n" ); document.write( "-1/2 = -3/2 + 2/2
\n" ); document.write( "-1/2 = -1/2; equality reigns
\n" ); document.write( ":
\n" ); document.write( "How about this? Make sense to you? \n" ); document.write( "
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