document.write( "Question 274704: Explain how you decide whether it is easier to solve a system by substitution or addition. \n" ); document.write( "

Algebra.Com's Answer #200434 by stanbon(75887) $\"\"$ $\"About$

You can put this solution on YOUR website!
Explain how you decide whether it is easier to solve a system by substitution or addition.
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\n" ); document.write( "There is no general answer to that question.
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\n" ); document.write( "You could say if you have x or y with a coefficient
\n" ); document.write( "of one, substitution MAY be more practical.
\n" ); document.write( "Example:
\n" ); document.write( "x + 3y = 5
\n" ); document.write( "2x + 5y = 8
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\n" ); document.write( "Solve the 1st equation for \"x:
\n" ); document.write( "x = 5-3y
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\n" ); document.write( "Substitute for \"x\" and solve for \"y\":
\n" ); document.write( "2(5-3y)+5y = 8
\n" ); document.write( "10 -6y + 5y = 8
\n" ); document.write( "-y = -2
\n" ); document.write( "y = 2
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\n" ); document.write( "Then substitute for y in x = 5-3y to solve for \"x\"
\n" ); document.write( "x = 5-3(2)
\n" ); document.write( "x = -1
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\n" ); document.write( "Solution: (-1,2)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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