document.write( "Question 572952: I am so confused on how your supposed to do this type of substitution problem.\r
\n" ); document.write( "\n" ); document.write( "y=-2x+6
\n" ); document.write( "3y-x+3=0 \n" ); document.write( "
Algebra.Com's Answer #368587 by mathsmiles(68)\"\" \"About 
You can put this solution on YOUR website!
What you have here are two equations with two variables, X and Y.
\n" ); document.write( "You want to substitute so that you end up with only one variable in an equation, which you can then solve.\r
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\n" ); document.write( "\n" ); document.write( "Lucky for you, they already put one of the equations in a form so that you have Y by itself.\r
\n" ); document.write( "\n" ); document.write( "Y = -2X+6
\n" ); document.write( "Take this and substitute this for Y in the second equation:
\n" ); document.write( "3Y-X+3=0 so ...
\n" ); document.write( "3(-2X+6) - X + 3 = 0
\n" ); document.write( "Multiplying out the parens:
\n" ); document.write( "-6X + 18 - X + 3 = 0
\n" ); document.write( "Now combine like terms so ...
\n" ); document.write( "(-6X - X) + (18 + 3) = 0
\n" ); document.write( "-7X + 21 = 0
\n" ); document.write( "Add 7X to both sides of the equation:
\n" ); document.write( "21 = 7X
\n" ); document.write( "Divide by 7 on both sides:
\n" ); document.write( "3 = X\r
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\n" ); document.write( "\n" ); document.write( "Now we need to figure Y:
\n" ); document.write( "Y = -2(3) + 6
\n" ); document.write( "Y = -6 + 6
\n" ); document.write( "Y = 0\r
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\n" ); document.write( "\n" ); document.write( "Checking:
\n" ); document.write( "3Y - X + 3 = 0
\n" ); document.write( "3(0) - 3 + 3 = 0
\n" ); document.write( "0-3+3=0 Correct!
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