document.write( "Question 389130: 1.Solve each system of equations using the elimination method.11x + 16y = 922x + 3y = 18\r
\n" ); document.write( "\n" ); document.write( "2.Solve each system of equations using the substitution method. 4x - y = 32y = -2 x + 70\r
\n" ); document.write( "\n" ); document.write( "3.Rewrite the linear programming problem as a maximization problem with constraints involving inequalities of the form≤ a constant (with the exception of the inequalities x≥0, y≥0, and z ≥0).
\n" ); document.write( "Minimize C = 2x-3y
\n" ); document.write( "Subject to 3x +5y ≥20
\n" ); document.write( " 3x+y≤16
\n" ); document.write( " -2x+y≤1
\n" ); document.write( " x≥0, y≥0\r
\n" ); document.write( "\n" ); document.write( "4. Find the distance between P and Q.P ( -8 , -9 ) and Q ( 10 , -9 ) \r
\n" ); document.write( "\n" ); document.write( "5.Find the distance between P and Q. P ( -9 , -5 ) Q ( 9 , -21 ) \r
\n" ); document.write( "\n" ); document.write( "6.Write an equation of the line that passes through the given two points ( -2 , 7 ), ( 4 , -23 )
\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "*[invoke calculating_slope -2, 7, 4, -23]\r
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Algebra.Com's Answer #275650 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
\r
\n" ); document.write( "\n" ); document.write( "1.Solve each system of equations using the elimination method.\r
\n" ); document.write( "\n" ); document.write( "\"11x+%2B+16y+=+92\"\r
\n" ); document.write( "\n" ); document.write( "\"2x+%2B+3y+=+18\" .....I guess this is your system....\r
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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( " \"11%2Ax%2B16%2Ay=92\"
\n" ); document.write( " \"2%2Ax%2B3%2Ay=18\"
\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 11 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 11 and 2 is 22, we need to multiply both sides of the top equation by 2 and multiply both sides of the bottom equation by -11 like this:
\n" ); document.write( "
\n" ); document.write( " \"2%2A%2811%2Ax%2B16%2Ay%29=%2892%29%2A2\" Multiply the top equation (both sides) by 2
\n" ); document.write( " \"-11%2A%282%2Ax%2B3%2Ay%29=%2818%29%2A-11\" Multiply the bottom equation (both sides) by -11
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So after multiplying we get this:
\n" ); document.write( " \"22%2Ax%2B32%2Ay=184\"
\n" ); document.write( " \"-22%2Ax-33%2Ay=-198\"
\n" ); document.write( "
\n" ); document.write( " Notice how 22 and -22 add to zero (ie \"22%2B-22=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( " \"%2822%2Ax-22%2Ax%29%2B%2832%2Ay-33%2Ay%29=184-198\"
\n" ); document.write( "
\n" ); document.write( " \"%2822-22%29%2Ax%2B%2832-33%29y=184-198\"
\n" ); document.write( "
\n" ); document.write( " \"cross%2822%2B-22%29%2Ax%2B%2832-33%29%2Ay=184-198\" Notice the x coefficients add to zero and cancel out. This means we've eliminated x altogether.
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\n" ); document.write( "
\n" ); document.write( " So after adding and canceling out the x terms we're left with:
\n" ); document.write( "
\n" ); document.write( " \"-1%2Ay=-14\"
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\n" ); document.write( " \"y=-14%2F-1\" Divide both sides by \"-1\" to solve for y
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\n" ); document.write( " \"y=14\" Reduce
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\n" ); document.write( "
\n" ); document.write( " Now plug this answer into the top equation \"11%2Ax%2B16%2Ay=92\" to solve for x
\n" ); document.write( "
\n" ); document.write( " \"11%2Ax%2B16%2814%29=92\" Plug in \"y=14\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"11%2Ax%2B224=92\" Multiply
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\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"11%2Ax=92-224\" Subtract \"224\" from both sides
\n" ); document.write( "
\n" ); document.write( " \"11%2Ax=-132\" Combine the terms on the right side
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\n" ); document.write( " \"cross%28%281%2F11%29%2811%29%29%2Ax=%28-132%29%281%2F11%29\" Multiply both sides by \"1%2F11\". This will cancel out \"11\" on the left side.
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\n" ); document.write( " \"x=-12\" 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=-12\", \"y=14\"
\n" ); document.write( "
\n" ); document.write( " which also looks like
\n" ); document.write( "
\n" ); document.write( " (\"-12\", \"14\")
\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( " \"11%2Ax%2B16%2Ay=92\"
\n" ); document.write( " \"2%2Ax%2B3%2Ay=18\"
\n" ); document.write( "
\n" ); document.write( " we get
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " graph of \"11%2Ax%2B16%2Ay=92\" (red) \"2%2Ax%2B3%2Ay=18\" (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 (\"-12\",\"14\"). This verifies our answer.

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\n" ); document.write( "\n" ); document.write( "2.Solve each system of equations using the substitution method. \r
\n" ); document.write( "\n" ); document.write( "\"4x+-+y+=+32\"\r
\n" ); document.write( "\n" ); document.write( "\"y+=+-2+x+%2B+70+\"..or..\"2+x+%2B+y+=70+\"\r
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Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
\n" ); document.write( " \"+system%28+%0D%0A++++4%5Cx+%2B+-1%5Cy+=+32%2C%0D%0A++++2%5Cx+%2B+1%5Cy+=+70+%29%0D%0A++\"We'll use substitution. After moving -1*y to the right, we get:
\n" ); document.write( " \"4%2Ax+=+32+-+-1%2Ay\", or \"x+=+32%2F4+-+-1%2Ay%2F4\". Substitute that
\n" ); document.write( " into another equation:
\n" ); document.write( " \"2%2A%2832%2F4+-+-1%2Ay%2F4%29+%2B+1%5Cy+=+70\" and simplify: So, we know that y=36. Since \"x+=+32%2F4+-+-1%2Ay%2F4\", x=17.
\n" ); document.write( "
\n" ); document.write( " Answer: \"system%28+x=17%2C+y=36+%29\".
\n" ); document.write( "

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\n" ); document.write( "\n" ); document.write( "4. Find the distance between P and Q.P ( -8 , -9 ) and Q ( 10 , -9 ) \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "
Solved by pluggable solver: Finding a distance between a point given by coordinates (x, y) and a line given by equation y=ax+b
We want to find the perpendicular distance between a point given by coordinates (\"-8\",\"-9\")
\n" ); document.write( " and a line given by equation \"y=10%2Ax%2B-9\"
\n" ); document.write( "
\n" ); document.write( " First, let's draw a diagram of general situation with point P (xo, yo) and
\n" ); document.write( " line L: y= a.x + b. The required distance is PC. (in the diagram below)
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Methodology
\n" ); document.write( " We will first find the vertices of the triangle in order to get the side lengths and then by applying
\n" ); document.write( " Sine Rule on right angle triangle PAB and PBC we will calculate the desired distance PC.
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Step1
\n" ); document.write( " Calculation of the vertices of triangle PAB:
\n" ); document.write( "
\n" ); document.write( " Draw a vertical line passing through the point 'P'. This line \"x=-8\" will cut the given line 'L'
\n" ); document.write( " at point 'A'. The X coordinate of A(x1) will be same as \"xo=-8\". To find the Y-coordinate of
\n" ); document.write( " 'A' we will use the fact that point 'A' lies on the given line 'L' and satisfies the equation
\n" ); document.write( " of the line 'L'
.
\n" ); document.write( " Now, plug this \"x1=-8\" in to the equation of line: y=10*x+-9
\n" ); document.write( " \"y1=10%2A-8+%2B-9\"
\n" ); document.write( " \"y1=-89\"
\n" ); document.write( "
\n" ); document.write( " Hence, Point (A)(\"x1=-8\",\"y1=-89\")
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Similarly,
\n" ); document.write( " Draw a horizontal line passing through the point 'P'. This line \"y=-9\" will cut the given line 'L'
\n" ); document.write( " at point 'B'. The Y coordinate of B(y2) will be same as \"yo=-9\". To find the X-coordinate of
\n" ); document.write( " B we will use the fact that point 'B' lies on the given line 'L' and satisfies the equation
\n" ); document.write( " of the line 'L'
.
\n" ); document.write( " Now, plug this \"y2=-9\" in to the equation of line: y=10*x+-9
\n" ); document.write( " \"-9=10%2Ax2%2B-9\"
\n" ); document.write( " \"x2=+%28-9--9%29%2F10\"
\n" ); document.write( " \"x2=0\"
\n" ); document.write( "
\n" ); document.write( " Hence, Point (B)(\"x2=0\",\"y2=-9\")
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Now, we have all the vertices of the triangle PAB
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Step2
\n" ); document.write( " Calculation of the side lengths using distance formula:
\n" ); document.write( "
\n" ); document.write( " \"d=sqrt%28%28x1-x2%29%5E2+%2B+%28y1-y2%29%5E2%29\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Hence, The side lengths PA, PB and AB are
\n" ); document.write( " \"PA=80\"
\n" ); document.write( " \"PB=8\"
\n" ); document.write( " \"AB=80.3990049689671\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Step3
\n" ); document.write( " Apply Sine rule on common angle B in triangle PAB and triangle PBC.
\n" ); document.write( " Both triangle PAB and triangle PBC are right angle triangle and points 'A', 'B' and 'C' lay on the given line L.
\n" ); document.write( "
\n" ); document.write( " \"Sin%28B%29=+AP%2FAB=PC%2FBP\"
\n" ); document.write( "
\n" ); document.write( " \"PC=%28AP%2ABP%29%2FAB=+7.96029752167991\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " PC is the required perpendicular distance of the point P (-8, -9) from line given
\n" ); document.write( " lineL1: y=10*x+-9.
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " For better understanding of this concept, look at the Lesson based on the above concept.
\n" ); document.write( " Lesson

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\n" ); document.write( "\n" ); document.write( "5.Find the distance between P and Q. P ( -9 , -5 ) Q ( 9 , -21 ) \r
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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 a distance between a point given by coordinates (x, y) and a line given by equation y=ax+b
We want to find the perpendicular distance between a point given by coordinates (\"-9\",\"-5\")
\n" ); document.write( " and a line given by equation \"y=9%2Ax%2B-21\"
\n" ); document.write( "
\n" ); document.write( " First, let's draw a diagram of general situation with point P (xo, yo) and
\n" ); document.write( " line L: y= a.x + b. The required distance is PC. (in the diagram below)
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Methodology
\n" ); document.write( " We will first find the vertices of the triangle in order to get the side lengths and then by applying
\n" ); document.write( " Sine Rule on right angle triangle PAB and PBC we will calculate the desired distance PC.
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Step1
\n" ); document.write( " Calculation of the vertices of triangle PAB:
\n" ); document.write( "
\n" ); document.write( " Draw a vertical line passing through the point 'P'. This line \"x=-9\" will cut the given line 'L'
\n" ); document.write( " at point 'A'. The X coordinate of A(x1) will be same as \"xo=-9\". To find the Y-coordinate of
\n" ); document.write( " 'A' we will use the fact that point 'A' lies on the given line 'L' and satisfies the equation
\n" ); document.write( " of the line 'L'
.
\n" ); document.write( " Now, plug this \"x1=-9\" in to the equation of line: y=9*x+-21
\n" ); document.write( " \"y1=9%2A-9+%2B-21\"
\n" ); document.write( " \"y1=-102\"
\n" ); document.write( "
\n" ); document.write( " Hence, Point (A)(\"x1=-9\",\"y1=-102\")
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Similarly,
\n" ); document.write( " Draw a horizontal line passing through the point 'P'. This line \"y=-5\" will cut the given line 'L'
\n" ); document.write( " at point 'B'. The Y coordinate of B(y2) will be same as \"yo=-5\". To find the X-coordinate of
\n" ); document.write( " B we will use the fact that point 'B' lies on the given line 'L' and satisfies the equation
\n" ); document.write( " of the line 'L'
.
\n" ); document.write( " Now, plug this \"y2=-5\" in to the equation of line: y=9*x+-21
\n" ); document.write( " \"-5=9%2Ax2%2B-21\"
\n" ); document.write( " \"x2=+%28-5--21%29%2F9\"
\n" ); document.write( " \"x2=1.77777777777778\"
\n" ); document.write( "
\n" ); document.write( " Hence, Point (B)(\"x2=1.77777777777778\",\"y2=-5\")
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Now, we have all the vertices of the triangle PAB
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Step2
\n" ); document.write( " Calculation of the side lengths using distance formula:
\n" ); document.write( "
\n" ); document.write( " \"d=sqrt%28%28x1-x2%29%5E2+%2B+%28y1-y2%29%5E2%29\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Hence, The side lengths PA, PB and AB are
\n" ); document.write( " \"PA=97\"
\n" ); document.write( " \"PB=10.7777777777778\"
\n" ); document.write( " \"AB=97.5969287110366\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Step3
\n" ); document.write( " Apply Sine rule on common angle B in triangle PAB and triangle PBC.
\n" ); document.write( " Both triangle PAB and triangle PBC are right angle triangle and points 'A', 'B' and 'C' lay on the given line L.
\n" ); document.write( "
\n" ); document.write( " \"Sin%28B%29=+AP%2FAB=PC%2FBP\"
\n" ); document.write( "
\n" ); document.write( " \"PC=%28AP%2ABP%29%2FAB=+10.7118580292601\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " PC is the required perpendicular distance of the point P (-9, -5) from line given
\n" ); document.write( " lineL1: y=9*x+-21.
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " For better understanding of this concept, look at the Lesson based on the above concept.
\n" ); document.write( " Lesson

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\n" ); document.write( "\n" ); document.write( "6.Write an equation of the line that passes through the given two points
\n" ); document.write( "( -2 , 7 ), ( 4 , -23 ) \r
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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 (\"-2\",\"7\") and (\"4\",\"-23\")
\n" ); document.write( "
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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\",\"7\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"4\",\"-23\"))
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"m=%28-23-7%29%2F%284--2%29\" Plug in \"y%5B2%5D=-23\",\"y%5B1%5D=7\",\"x%5B2%5D=4\",\"x%5B1%5D=-2\" (these are the coordinates of given points)
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\n" ); document.write( "
\n" ); document.write( " \"m=+-30%2F6\" Subtract the terms in the numerator \"-23-7\" to get \"-30\". Subtract the terms in the denominator \"4--2\" to get \"6\"
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\n" ); document.write( " \"m=-5\" Reduce
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\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So the slope is
\n" ); document.write( "
\n" ); document.write( " \"m=-5\"
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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:
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\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
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y-7=%28-5%29%28x--2%29\" Plug in \"m=-5\", \"x%5B1%5D=-2\", and \"y%5B1%5D=7\" (these values are given)
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\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y-7=%28-5%29%28x%2B2%29\" Rewrite \"x--2\" as \"x%2B2\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y-7=-5x%2B%28-5%29%282%29\" Distribute \"-5\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y-7=-5x-10\" Multiply \"-5\" and \"2\" to get \"-10%2F1\". Now reduce \"-10%2F1\" to get \"-10\"
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( " \"y=-5x-10%2B7\" Add \"7\" to both sides to isolate y
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y=-5x-3\" Combine like terms \"-10\" and \"7\" to get \"-3\"
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\n" ); document.write( " ------------------------------------------------------------------------------------------------------------
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\n" ); document.write( " Answer:
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So the equation of the line which goes through the points (\"-2\",\"7\") and (\"4\",\"-23\") is:\"y=-5x-3\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " The equation is now in \"y=mx%2Bb\" form (which is slope-intercept form) where the slope is \"m=-5\" and the y-intercept is \"b=-3\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Notice if we graph the equation \"y=-5x-3\" and plot the points (\"-2\",\"7\") and (\"4\",\"-23\"), we get this: (note: if you need help with graphing, check out this solver)
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\n" ); document.write( " Graph of \"y=-5x-3\" through the points (\"-2\",\"7\") and (\"4\",\"-23\")
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\n" ); document.write( " Notice how the two points lie on the line. This graphically verifies our answer.
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