document.write( "Question 1203124: A triangle is formed by the vertices A(1, 2), B(-5, -3), and C(1,-4)\r
\n" ); document.write( "\n" ); document.write( "a.) Classify this triangle\r
\n" ); document.write( "\n" ); document.write( "b.) Identify the centroid using the intersection of medians\r
\n" ); document.write( "\n" ); document.write( "c.) There is a formula for centroid, which is (x1+x2+x3 ÷ 3 , y1+y2+y3 ÷ 3), calculate the centroid using this formula. Do your answers match?
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Algebra.Com's Answer #838432 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "A triangle is formed by the vertices A(\"1\", \"2\"), B(\"-5\", \"-3\"), and C(\"1\",\"-4\")\r
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\n" ); document.write( "\n" ); document.write( "a.) Classify this triangle\r
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\n" ); document.write( "\n" ); document.write( "check the distance between \"AB\", \"AC\", and \"BC\"\r
\n" ); document.write( "\n" ); document.write( "\"AB\"\r
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Solved by pluggable solver: Distance Between 2 points
The distance formula is \"sqrt%28%28%28x%5B2%5D-x%5B1%5D%29%5E2%29%2B%28%28y%5B2%5D-y%5B1%5D%29%5E2%29%29\". Plug in the numbers,\r
\n" ); document.write( "\n" ); document.write( "\"sqrt%28%28%28-5-%281%29%29%5E2%29%2B%28%28-3-%282%29%29%5E2%29%29\" \r
\n" ); document.write( "\n" ); document.write( "\"sqrt%28-6%5E2%2B-5%5E2%29\" The distance is 7.81024967590665.\r
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\n" ); document.write( "\n" ); document.write( "\"AB=7.8\"\r
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\n" ); document.write( "\n" ); document.write( "\"AC\"\r
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Solved by pluggable solver: Distance Between 2 points
The distance formula is \"sqrt%28%28%28x%5B2%5D-x%5B1%5D%29%5E2%29%2B%28%28y%5B2%5D-y%5B1%5D%29%5E2%29%29\". Plug in the numbers,\r
\n" ); document.write( "\n" ); document.write( "\"sqrt%28%28%281-%281%29%29%5E2%29%2B%28%28-4-%282%29%29%5E2%29%29\" \r
\n" ); document.write( "\n" ); document.write( "\"sqrt%280%5E2%2B-6%5E2%29\" The distance is 6.\r
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\n" ); document.write( "\n" ); document.write( "\"AC=6\"\r
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\n" ); document.write( "\n" ); document.write( "and \"BC\"\r
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Solved by pluggable solver: Distance Between 2 points
The distance formula is \"sqrt%28%28%28x%5B2%5D-x%5B1%5D%29%5E2%29%2B%28%28y%5B2%5D-y%5B1%5D%29%5E2%29%29\". Plug in the numbers,\r
\n" ); document.write( "\n" ); document.write( "\"sqrt%28%28%281-%28-5%29%29%5E2%29%2B%28%28-4-%28-3%29%29%5E2%29%29\" \r
\n" ); document.write( "\n" ); document.write( "\"sqrt%286%5E2%2B-1%5E2%29\" The distance is 6.08276253029822.\r
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\n" ); document.write( "\n" ); document.write( "\"BC=6.08\"\r
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\n" ); document.write( "\n" ); document.write( "so, the lengths of the sides are different and we have a \"scalene\" triangle \r
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\n" ); document.write( "\n" ); document.write( "b.) Identify the centroid using the intersection of medians\r
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\n" ); document.write( "\n" ); document.write( "find midpoints:\r
\n" ); document.write( "\n" ); document.write( "A(\"1\", \"2\"), B(\"-5\", \"-3\") => (\"x1\",\"y1\")=(\"%281-5%29%2F2\", \"%282-3%29%2F2%29=%28%7B%7B%7B-2%2C+%7B%7B%7B-1%2F2%29%0D%0A%0D%0A%0D%0AA%28%7B%7B%7B1\",\"+2\"), C(\"1\",\"-4\")=> (\"x2\",\"y2\")= (\"%281%2B1%29%2F2\", \"%282-4%29%2F2\")=(\"1\", \"-1\")\r
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\n" ); document.write( "\n" ); document.write( " B(\"-5\", \"-3\"), C(\"1\",\"-4\")=> (\"x3\",\"y3\")= (\"%28-5%2B1%29%2F2\", \"%28-3-4%29%2F2\")=(\"-2\", \"-7%2F2\")\r
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\n" ); document.write( "\n" ); document.write( "find equations of the lines passing through the points (\"-2\", \"-1%2F2\") and (\"1\", \"-4\"), as through the points (\"-5\", \"-3\") and (\"1\",\"+-1\")\r
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Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (\"-2\",\"-1%2F2\") and (\"1\",\"-4\")
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\n" ); document.write( " \"m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\" Start with the slope formula (note: (\"x%5B1%5D\",\"y%5B1%5D\") is the first point (\"-2\",\"-1%2F2\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"1\",\"-4\"))
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\n" ); document.write( " \"m=%28-4--1%2F2%29%2F%281--2%29\" Plug in \"y%5B2%5D=-4\",\"y%5B1%5D=-1%2F2\",\"x%5B2%5D=1\",\"x%5B1%5D=-2\" (these are the coordinates of given points)
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\n" ); document.write( " \"m=+%28-7%2F2%29%2F%283%2F1%29\" Subtract (note: if you need help with subtracting or dividing fractions, check out this solver)
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\n" ); document.write( " \"m=-7%2F6\" Divide the fractions
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\n" ); document.write( " So the slope is
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\n" ); document.write( " \"m=-7%2F6\"
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\n" ); document.write( "Now let's use the point-slope formula to find the equation of the line:
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\n" ); document.write( "
\n" ); document.write( " ------Point-Slope Formula------
\n" ); document.write( " \"y-y%5B1%5D=m%28x-x%5B1%5D%29\" where \"m\" is the slope, and (\"x%5B1%5D\",\"y%5B1%5D\") is one of the given points
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\n" ); document.write( "
\n" ); document.write( " So lets use the Point-Slope Formula to find the equation of the line
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\n" ); document.write( " \"y--1%2F2=%28-7%2F6%29%28x--2%29\" Plug in \"m=-7%2F6\", \"x%5B1%5D=-2\", and \"y%5B1%5D=-1%2F2\" (these values are given)
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\n" ); document.write( " \"y%2B1%2F2=%28-7%2F6%29%28x--2%29\" Rewrite \"y--1%2F2\" as \"y%2B1%2F2\"
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\n" ); document.write( " \"y%2B1%2F2=%28-7%2F6%29%28x%2B2%29\" Rewrite \"x--2\" as \"x%2B2\"
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\n" ); document.write( " \"y%2B1%2F2=%28-7%2F6%29x%2B%28-7%2F6%29%282%29\" Distribute \"-7%2F6\"
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\n" ); document.write( "
\n" ); document.write( " \"y%2B1%2F2=%28-7%2F6%29x-7%2F3\" Multiply \"-7%2F6\" and \"2\" to get \"-14%2F6\". Now reduce \"-14%2F6\" to get \"-7%2F3\"
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( " \"y=%28-7%2F6%29x-7%2F3-1%2F2\" Subtract \"1%2F2\" from both sides to isolate y
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\n" ); document.write( " \"y=%28-7%2F6%29x-17%2F6\" Combine like terms \"-7%2F3\" and \"-1%2F2\" to get \"-17%2F6\" (note: if you need help with combining fractions, check out this solver)
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\n" ); document.write( " Answer:
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\n" ); document.write( " So the equation of the line which goes through the points (\"-2\",\"-1%2F2\") and (\"1\",\"-4\") is:\"y=%28-7%2F6%29x-17%2F6\"
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\n" ); document.write( " The equation is now in \"y=mx%2Bb\" form (which is slope-intercept form) where the slope is \"m=-7%2F6\" and the y-intercept is \"b=-17%2F6\"
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\n" ); document.write( "
\n" ); document.write( " Notice if we graph the equation \"y=%28-7%2F6%29x-17%2F6\" and plot the points (\"-2\",\"-1%2F2\") and (\"1\",\"-4\"), we get this: (note: if you need help with graphing, check out this solver)
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\n" ); document.write( "
\n" ); document.write( " Graph of \"y=%28-7%2F6%29x-17%2F6\" through the points (\"-2\",\"-1%2F2\") and (\"1\",\"-4\")
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\n" ); document.write( "
\n" ); document.write( " Notice how the two points lie on the line. This graphically verifies our answer.
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\n" ); document.write( "\n" ); document.write( "\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "
Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (\"-5\",\"-3\") and (\"1\",\"-1\")
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\" Start with the slope formula (note: (\"x%5B1%5D\",\"y%5B1%5D\") is the first point (\"-5\",\"-3\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"1\",\"-1\"))
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\n" ); document.write( " \"m=%28-1--3%29%2F%281--5%29\" Plug in \"y%5B2%5D=-1\",\"y%5B1%5D=-3\",\"x%5B2%5D=1\",\"x%5B1%5D=-5\" (these are the coordinates of given points)
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\n" ); document.write( " \"m=+2%2F6\" Subtract the terms in the numerator \"-1--3\" to get \"2\". Subtract the terms in the denominator \"1--5\" to get \"6\"
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\n" ); document.write( " \"m=1%2F3\" Reduce
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\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So the slope is
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\n" ); document.write( " \"m=1%2F3\"
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\n" ); document.write( "
\n" ); document.write( " ------------------------------------------------
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\n" ); document.write( "
\n" ); document.write( "Now let's use the point-slope formula to find the equation of the line:
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " ------Point-Slope Formula------
\n" ); document.write( " \"y-y%5B1%5D=m%28x-x%5B1%5D%29\" where \"m\" is the slope, and (\"x%5B1%5D\",\"y%5B1%5D\") is one of the given points
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So lets use the Point-Slope Formula to find the equation of the line
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\n" ); document.write( "
\n" ); document.write( " \"y--3=%281%2F3%29%28x--5%29\" Plug in \"m=1%2F3\", \"x%5B1%5D=-5\", and \"y%5B1%5D=-3\" (these values are given)
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\n" ); document.write( " \"y%2B3=%281%2F3%29%28x--5%29\" Rewrite \"y--3\" as \"y%2B3\"
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\n" ); document.write( " \"y%2B3=%281%2F3%29%28x%2B5%29\" Rewrite \"x--5\" as \"x%2B5\"
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\n" ); document.write( "
\n" ); document.write( " \"y%2B3=%281%2F3%29x%2B%281%2F3%29%285%29\" Distribute \"1%2F3\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y%2B3=%281%2F3%29x%2B5%2F3\" Multiply \"1%2F3\" and \"5\" to get \"5%2F3\"
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( " \"y=%281%2F3%29x%2B5%2F3-3\" Subtract \"3\" from both sides to isolate y
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\n" ); document.write( " \"y=%281%2F3%29x-4%2F3\" Combine like terms \"5%2F3\" and \"-3\" to get \"-4%2F3\" (note: if you need help with combining fractions, check out this solver)
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\n" ); document.write( " Answer:
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\n" ); document.write( " So the equation of the line which goes through the points (\"-5\",\"-3\") and (\"1\",\"-1\") is:\"y=%281%2F3%29x-4%2F3\"
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\n" ); document.write( " The equation is now in \"y=mx%2Bb\" form (which is slope-intercept form) where the slope is \"m=1%2F3\" and the y-intercept is \"b=-4%2F3\"
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\n" ); document.write( "
\n" ); document.write( " Notice if we graph the equation \"y=%281%2F3%29x-4%2F3\" and plot the points (\"-5\",\"-3\") and (\"1\",\"-1\"), we get this: (note: if you need help with graphing, check out this solver)
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\n" ); document.write( "
\n" ); document.write( " Graph of \"y=%281%2F3%29x-4%2F3\" through the points (\"-5\",\"-3\") and (\"1\",\"-1\")
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\n" ); document.write( "
\n" ); document.write( " Notice how the two points lie on the line. This graphically verifies our answer.
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\n" ); document.write( "\n" ); document.write( "\"+y=%28-7%2F6%29x-17%2F6\"
\n" ); document.write( "\"y=%281%2F3%29x-4%2F3\"\r
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\n" ); document.write( "\n" ); document.write( "find intersection:\r
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Solved by pluggable solver: Solving a System of Linear Equations by Elimination/Addition
TEST
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\n" ); document.write( " \"%287%2F6%29%2Ax%2B%281%29%2Ay=-17%2F6\" Start with the first equation
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\n" ); document.write( " \"6%28%287%2F6%29%2Ax%2B%281%29%2Ay%29=%286%29%2A%28-17%2F6%29\" Multiply both sides by the LCD 6
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\n" ); document.write( " \"7%2Ax%2B6%2Ay=-17\"Distribute and simplify
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\n" ); document.write( "
\n" ); document.write( " \"%28-1%2F3%29%2Ax%2B%281%29%2Ay=-4%2F3\" Start with the second equation
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\n" ); document.write( " \"3%28%28-1%2F3%29%2Ax%2B%281%29%2Ay%29=%283%29%2A%28-4%2F3%29\" Multiply both sides by the LCD 3
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\n" ); document.write( "
\n" ); document.write( " \"-1%2Ax%2B3%2Ay=-4\" Distribute and simplify
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\n" ); document.write( "
\n" ); document.write( " Lets start with the given system of linear equations
\n" ); document.write( "
\n" ); document.write( " \"7%2Ax%2B6%2Ay=-17\"
\n" ); document.write( " \"-1%2Ax%2B3%2Ay=-4\"
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\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).
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\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.
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\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 7 and -1 to some equal number, we could try to get them to the LCM.
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\n" ); document.write( " Since the LCM of 7 and -1 is -7, we need to multiply both sides of the top equation by -1 and multiply both sides of the bottom equation by -7 like this:
\n" ); document.write( "
\n" ); document.write( " \"-1%2A%287%2Ax%2B6%2Ay%29=%28-17%29%2A-1\" Multiply the top equation (both sides) by -1
\n" ); document.write( " \"-7%2A%28-1%2Ax%2B3%2Ay%29=%28-4%29%2A-7\" Multiply the bottom equation (both sides) by -7
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\n" ); document.write( " So after multiplying we get this:
\n" ); document.write( " \"-7%2Ax-6%2Ay=17\"
\n" ); document.write( " \"7%2Ax-21%2Ay=28\"
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\n" ); document.write( " Notice how -7 and 7 add to zero (ie \"-7%2B7=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( " \"%28-7%2Ax%2B7%2Ax%29-6%2Ay-21%2Ay%29=17%2B28\"
\n" ); document.write( "
\n" ); document.write( " \"%28-7%2B7%29%2Ax-6-21%29y=17%2B28\"
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\n" ); document.write( " \"cross%28-7%2B7%29%2Ax%2B%28-6-21%29%2Ay=17%2B28\" 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:
\n" ); document.write( "
\n" ); document.write( " \"-27%2Ay=45\"
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\n" ); document.write( " \"y=45%2F-27\" Divide both sides by \"-27\" to solve for y
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\n" ); document.write( " \"y=-5%2F3\" Reduce
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\n" ); document.write( "
\n" ); document.write( " Now plug this answer into the top equation \"7%2Ax%2B6%2Ay=-17\" to solve for x
\n" ); document.write( "
\n" ); document.write( " \"7%2Ax%2B6%28-5%2F3%29=-17\" Plug in \"y=-5%2F3\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"7%2Ax-30%2F3=-17\" Multiply
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\n" ); document.write( "
\n" ); document.write( " \"7%2Ax-10=-17\" Reduce
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\n" ); document.write( "
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\n" ); document.write( " \"7%2Ax=-17%2B10\" Subtract \"-10\" from both sides
\n" ); document.write( "
\n" ); document.write( " \"7%2Ax=-7\" Combine the terms on the right side
\n" ); document.write( "
\n" ); document.write( " \"cross%28%281%2F7%29%287%29%29%2Ax=%28-7%29%281%2F7%29\" Multiply both sides by \"1%2F7\". This will cancel out \"7\" on the left side.
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"x=-1\" Multiply the terms on the right side
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\n" ); document.write( " So our answer is
\n" ); document.write( "
\n" ); document.write( " \"x=-1\", \"y=-5%2F3\"
\n" ); document.write( "
\n" ); document.write( " which also looks like
\n" ); document.write( "
\n" ); document.write( " (\"-1\", \"-5%2F3\")
\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( " \"7%2Ax%2B6%2Ay=-17\"
\n" ); document.write( " \"-1%2Ax%2B3%2Ay=-4\"
\n" ); document.write( "
\n" ); document.write( " we get
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " graph of \"7%2Ax%2B6%2Ay=-17\" (red) \"-1%2Ax%2B3%2Ay=-4\" (green) (hint: you may have to solve for y to graph these) and the intersection of the lines (blue circle).
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " and we can see that the two equations intersect at (\"-1\",\"-5%2F3\"). This verifies our answer.
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