document.write( "Question 83798: Solve, 31x-8(3x-0.745)=6x+0.205\r
\n" ); document.write( "\n" ); document.write( "Solve each of the following systems by addition. If a unique solution doesn't exsist, state whether the system is inconsistent or dependent.\r
\n" ); document.write( "\n" ); document.write( "1.{ a.2x+3y=1
\n" ); document.write( " b.5x+3y=16
\n" ); document.write( "2.{ a. x+5y=10
\n" ); document.write( " b.-2-10y=-20\r
\n" ); document.write( "\n" ); document.write( "thank you so much, and thank you for your time.\r
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Algebra.Com's Answer #60270 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\"31x-8%283x-0.745%29=6x%2B0.205\"
\n" ); document.write( "\"31x-24x%2B5.96=6x%2B0.205\" Distribute
\n" ); document.write( "\"7x-5.96=6x%2B0.205\" Combine like terms
\n" ); document.write( "\"7x=6x%2B0.205-5.96\" Subtract 5.96 to both sides
\n" ); document.write( "\"7x-6x=0.205-5.96\" Subtract 6x from both sides
\n" ); document.write( "\"x=-5.755\" Combine like terms
\n" ); document.write( "So our answer is
\n" ); document.write( "\"x=-5.755\"\r
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\n" ); document.write( "\n" ); document.write( "1.
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Solved by pluggable solver: Solving a System of Linear Equations by Elimination/Addition

\n" ); document.write( "
\n" ); document.write( " Lets start with the given system of linear equations
\n" ); document.write( "
\n" ); document.write( " \"2%2Ax%2B3%2Ay=1\"
\n" ); document.write( " \"5%2Ax%2B3%2Ay=16\"
\n" ); document.write( "
\n" ); document.write( " In order to solve for one variable, we must eliminate the other variable. So if we wanted to solve for y, we would have to eliminate x (or vice versa).
\n" ); document.write( "
\n" ); document.write( " So lets eliminate x. In order to do that, we need to have both x coefficients that are equal but have opposite signs (for instance 2 and -2 are equal but have opposite signs). This way they will add to zero.
\n" ); document.write( "
\n" ); document.write( " So to make the x coefficients equal but opposite, we need to multiply both x coefficients by some number to get them to an equal number. So if we wanted to get 2 and 5 to some equal number, we could try to get them to the LCM.
\n" ); document.write( "
\n" ); document.write( " Since the LCM of 2 and 5 is 10, we need to multiply both sides of the top equation by 5 and multiply both sides of the bottom equation by -2 like this:
\n" ); document.write( "
\n" ); document.write( " \"5%2A%282%2Ax%2B3%2Ay%29=%281%29%2A5\" Multiply the top equation (both sides) by 5
\n" ); document.write( " \"-2%2A%285%2Ax%2B3%2Ay%29=%2816%29%2A-2\" Multiply the bottom equation (both sides) by -2
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\n" ); document.write( "
\n" ); document.write( " So after multiplying we get this:
\n" ); document.write( " \"10%2Ax%2B15%2Ay=5\"
\n" ); document.write( " \"-10%2Ax-6%2Ay=-32\"
\n" ); document.write( "
\n" ); document.write( " Notice how 10 and -10 add to zero (ie \"10%2B-10=0\")
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\n" ); document.write( " Now add the equations together. In order to add 2 equations, group like terms and combine them
\n" ); document.write( " \"%2810%2Ax-10%2Ax%29%2B%2815%2Ay-6%2Ay%29=5-32\"
\n" ); document.write( "
\n" ); document.write( " \"%2810-10%29%2Ax%2B%2815-6%29y=5-32\"
\n" ); document.write( "
\n" ); document.write( " \"cross%2810%2B-10%29%2Ax%2B%2815-6%29%2Ay=5-32\" Notice the x coefficients add to zero and cancel out. This means we've eliminated x altogether.
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\n" ); document.write( " So after adding and canceling out the x terms we're left with:
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\n" ); document.write( " \"9%2Ay=-27\"
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\n" ); document.write( " \"y=-27%2F9\" Divide both sides by \"9\" to solve for y
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\n" ); document.write( " \"y=-3\" Reduce
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\n" ); document.write( "
\n" ); document.write( " Now plug this answer into the top equation \"2%2Ax%2B3%2Ay=1\" to solve for x
\n" ); document.write( "
\n" ); document.write( " \"2%2Ax%2B3%28-3%29=1\" Plug in \"y=-3\"
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\n" ); document.write( "
\n" ); document.write( " \"2%2Ax-9=1\" Multiply
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\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"2%2Ax=1%2B9\" Subtract \"-9\" from both sides
\n" ); document.write( "
\n" ); document.write( " \"2%2Ax=10\" Combine the terms on the right side
\n" ); document.write( "
\n" ); document.write( " \"cross%28%281%2F2%29%282%29%29%2Ax=%2810%29%281%2F2%29\" Multiply both sides by \"1%2F2\". This will cancel out \"2\" on the left side.
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\n" ); document.write( " \"x=5\" Multiply the terms on the right side
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\n" ); document.write( "
\n" ); document.write( " So our answer is
\n" ); document.write( "
\n" ); document.write( " \"x=5\", \"y=-3\"
\n" ); document.write( "
\n" ); document.write( " which also looks like
\n" ); document.write( "
\n" ); document.write( " (\"5\", \"-3\")
\n" ); document.write( "
\n" ); document.write( " Notice if we graph the equations (if you need help with graphing, check out this solver)
\n" ); document.write( "
\n" ); document.write( " \"2%2Ax%2B3%2Ay=1\"
\n" ); document.write( " \"5%2Ax%2B3%2Ay=16\"
\n" ); document.write( "
\n" ); document.write( " we get
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\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " graph of \"2%2Ax%2B3%2Ay=1\" (red) \"5%2Ax%2B3%2Ay=16\" (green) (hint: you may have to solve for y to graph these) and the intersection of the lines (blue circle).
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\n" ); document.write( "
\n" ); document.write( " and we can see that the two equations intersect at (\"5\",\"-3\"). This verifies our answer.

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\n" ); document.write( "\n" ); document.write( "2.
\n" ); document.write( "\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "
Solved by pluggable solver: Solving a System of Linear Equations by Elimination/Addition

\n" ); document.write( "
\n" ); document.write( " Lets start with the given system of linear equations
\n" ); document.write( "
\n" ); document.write( " \"1%2Ax%2B5%2Ay=10\"
\n" ); document.write( " \"-2%2Ax-10%2Ay=-20\"
\n" ); document.write( "
\n" ); document.write( " In order to solve for one variable, we must eliminate the other variable. So if we wanted to solve for y, we would have to eliminate x (or vice versa).
\n" ); document.write( "
\n" ); document.write( " So lets eliminate x. In order to do that, we need to have both x coefficients that are equal but have opposite signs (for instance 2 and -2 are equal but have opposite signs). This way they will add to zero.
\n" ); document.write( "
\n" ); document.write( " So to make the x coefficients equal but opposite, we need to multiply both x coefficients by some number to get them to an equal number. So if we wanted to get 1 and -2 to some equal number, we could try to get them to the LCM.
\n" ); document.write( "
\n" ); document.write( " Since the LCM of 1 and -2 is -2, we need to multiply both sides of the top equation by -2 and multiply both sides of the bottom equation by -1 like this:
\n" ); document.write( "
\n" ); document.write( " \"-2%2A%281%2Ax%2B5%2Ay%29=%2810%29%2A-2\" Multiply the top equation (both sides) by -2
\n" ); document.write( " \"-1%2A%28-2%2Ax-10%2Ay%29=%28-20%29%2A-1\" Multiply the bottom equation (both sides) by -1
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So after multiplying we get this:
\n" ); document.write( " \"-2%2Ax-10%2Ay=-20\"
\n" ); document.write( " \"2%2Ax%2B10%2Ay=20\"
\n" ); document.write( "
\n" ); document.write( " Notice how -2 and 2 add to zero, -10 and 10 add to zero, -20 and 20 and to zero (ie \"-2%2B2=0\") \"-10%2B10=0\", and \"-20%2B20=0\")
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So we're left with
\n" ); document.write( "
\n" ); document.write( " \"0=0\"
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\n" ); document.write( "
\n" ); document.write( " which means any x or y value will satisfy the system of equations. So there are an infinite number of solutions
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\n" ); document.write( " So this system is dependent
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