document.write( "Question 143503This question is from textbook algebra 1
\n" ); document.write( ": How do you find an answer to the question:
\n" ); document.write( "3x+y=3
\n" ); document.write( "7x+2y=1
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Algebra.Com's Answer #104445 by nabla(475)\"\" \"About 
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The quickest way would be to subtract the first equation from the second giving you a new system:
\n" ); document.write( "3x+y=3
\n" ); document.write( "4x+y=-2
\n" ); document.write( "Now you can repeat that, giving another system:
\n" ); document.write( "3x+y=3
\n" ); document.write( "x=-5\r
\n" ); document.write( "\n" ); document.write( "Now plug the solution for x into the first equation:
\n" ); document.write( "3(-5)+y=3 implies y=18
\n" ); document.write( "set: (-5,18)\r
\n" ); document.write( "\n" ); document.write( "Here is another way to do it:
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Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
\n" ); document.write( " \"+system%28+%0D%0A++++3%5Cx+%2B+1%5Cy+=+3%2C%0D%0A++++7%5Cx+%2B+2%5Cy+=+1+%29%0D%0A++\"We'll use substitution. After moving 1*y to the right, we get:
\n" ); document.write( " \"3%2Ax+=+3+-+1%2Ay\", or \"x+=+3%2F3+-+1%2Ay%2F3\". Substitute that
\n" ); document.write( " into another equation:
\n" ); document.write( " \"7%2A%283%2F3+-+1%2Ay%2F3%29+%2B+2%5Cy+=+1\" and simplify: So, we know that y=18. Since \"x+=+3%2F3+-+1%2Ay%2F3\", x=-5.
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\n" ); document.write( " Answer: \"system%28+x=-5%2C+y=18+%29\".
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