document.write( "Question 369116: How do you solve a problem like this? y= 3x and 3x+4y= 30 \n" ); document.write( "

Algebra.Com's Answer #263028 by neatmath(302) $\"\"$ $\"About$

You can put this solution on YOUR website!
The easiest way is by substitution.
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\n" ); document.write( "\n" ); document.write( "y=3x
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\n" ); document.write( "\n" ); document.write( "3x+4y=30
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\n" ); document.write( "\n" ); document.write( "Since we know what y equals in the first equation (3x), we will substitute that in for the value of y in the second equation.
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\n" ); document.write( "\n" ); document.write( "So we now have
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\n" ); document.write( "\n" ); document.write( "3x+4*(3x)=30
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\n" ); document.write( "\n" ); document.write( "3x+12x=30
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\n" ); document.write( "\n" ); document.write( "15x=30
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\n" ); document.write( "\n" ); document.write( "x=2
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\n" ); document.write( "\n" ); document.write( "Since we know what x has to be, we can just substitute that value into either equation to find the value of y.
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\n" ); document.write( "\n" ); document.write( "y=3x
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\n" ); document.write( "\n" ); document.write( "y=3*2
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\n" ); document.write( "\n" ); document.write( "y=6
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\n" ); document.write( "\n" ); document.write( "The solution to this system of equations is x=2 and y=6, or the point (6,2)
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\n" ); document.write( "\n" ); document.write( "When dealing with a system of 2 linear equations, the solution to the system will always be a singe point, unless the two lines are parallel or are actually the same line. :)
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\n" ); document.write( "\n" ); document.write( "I hope this helps!
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