Algebra.Com's Answer #275650 by MathLover1(20850)  You can put this solution on YOUR website! \r \n" );
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document.write( "1.Solve each system of equations using the elimination method.\r \n" );
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document.write( " .....I guess this is your system....\r \n" );
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document.write( " Solved by pluggable solver: Solving a System of Linear Equations by Elimination/Addition | \n" );
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document.write( " Lets start with the given system of linear equations \n" );
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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" );
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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" );
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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" );
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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" );
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document.write( " Multiply the top equation (both sides) by 2 \n" );
document.write( " Multiply the bottom equation (both sides) by -11 \n" );
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document.write( " So after multiplying we get this: \n" );
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document.write( " Notice how 22 and -22 add to zero (ie ) \n" );
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document.write( " Now add the equations together. In order to add 2 equations, group like terms and combine them \n" );
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document.write( " Notice the x coefficients add to zero and cancel out. This means we've eliminated x altogether. \n" );
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document.write( " So after adding and canceling out the x terms we're left with: \n" );
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document.write( " Divide both sides by to solve for y \n" );
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document.write( " Reduce \n" );
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document.write( " Now plug this answer into the top equation to solve for x \n" );
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document.write( " Plug in  \n" );
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document.write( " Multiply \n" );
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document.write( " Subtract from both sides \n" );
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document.write( " Combine the terms on the right side \n" );
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document.write( " Multiply both sides by . This will cancel out on the left side. \n" );
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document.write( " Multiply the terms on the right side \n" );
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document.write( " So our answer is \n" );
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document.write( " ,  \n" );
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document.write( " which also looks like \n" );
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document.write( " ( , ) \n" );
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document.write( " Notice if we graph the equations (if you need help with graphing, check out this solver) \n" );
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document.write( " we get \n" );
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document.write( " graph of (red) (green) (hint: you may have to solve for y to graph these) and the intersection of the lines (blue circle). \n" );
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document.write( " and we can see that the two equations intersect at ( , ). This verifies our answer. | \n" );
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document.write( "2.Solve each system of equations using the substitution method. \r \n" );
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document.write( " ..or.. \r \n" );
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document.write( " Solved by pluggable solver: SOLVE linear system by SUBSTITUTION | \n" );
document.write( "Solve: \n" );
document.write( " We'll use substitution. After moving -1*y to the right, we get: \n" );
document.write( " , or . Substitute that \n" );
document.write( " into another equation: \n" );
document.write( " and simplify: So, we know that y=36. Since , x=17. \n" );
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document.write( " Answer: . \n" );
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document.write( "4. Find the distance between P and Q.P ( -8 , -9 ) and Q ( 10 , -9 ) \r \n" );
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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 | \n" );
document.write( "We want to find the perpendicular distance between a point given by coordinates ( , ) \n" );
document.write( " and a line given by equation  \n" );
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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" );
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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" );
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document.write( " Step1 \n" );
document.write( " Calculation of the vertices of triangle PAB: \n" );
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document.write( " Draw a vertical line passing through the point 'P'. This line will cut the given line 'L' \n" );
document.write( " at point 'A'. The X coordinate of A(x1) will be same as . 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 in to the equation of line: y=10*x+-9 \n" );
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document.write( " Hence, Point (A)( , ) \n" );
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document.write( " Similarly, \n" );
document.write( " Draw a horizontal line passing through the point 'P'. This line will cut the given line 'L' \n" );
document.write( " at point 'B'. The Y coordinate of B(y2) will be same as . 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 in to the equation of line: y=10*x+-9 \n" );
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document.write( " Hence, Point (B)( , ) \n" );
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document.write( " Now, we have all the vertices of the triangle PAB \n" );
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document.write( " Step2 \n" );
document.write( " Calculation of the side lengths using distance formula: \n" );
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document.write( " Hence, The side lengths PA, PB and AB are \n" );
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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" );
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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" );
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document.write( " For better understanding of this concept, look at the Lesson based on the above concept. \n" );
document.write( " Lesson | \n" );
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document.write( "5.Find the distance between P and Q. P ( -9 , -5 ) Q ( 9 , -21 ) \r \n" );
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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 | \n" );
document.write( "We want to find the perpendicular distance between a point given by coordinates ( , ) \n" );
document.write( " and a line given by equation  \n" );
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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" );
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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" );
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document.write( " Step1 \n" );
document.write( " Calculation of the vertices of triangle PAB: \n" );
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document.write( " Draw a vertical line passing through the point 'P'. This line will cut the given line 'L' \n" );
document.write( " at point 'A'. The X coordinate of A(x1) will be same as . 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 in to the equation of line: y=9*x+-21 \n" );
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document.write( " Hence, Point (A)( , ) \n" );
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document.write( " Similarly, \n" );
document.write( " Draw a horizontal line passing through the point 'P'. This line will cut the given line 'L' \n" );
document.write( " at point 'B'. The Y coordinate of B(y2) will be same as . 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 in to the equation of line: y=9*x+-21 \n" );
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document.write( " Hence, Point (B)( , ) \n" );
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document.write( " Now, we have all the vertices of the triangle PAB \n" );
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document.write( " Step2 \n" );
document.write( " Calculation of the side lengths using distance formula: \n" );
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document.write( " Hence, The side lengths PA, PB and AB are \n" );
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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" );
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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" );
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document.write( " For better understanding of this concept, look at the Lesson based on the above concept. \n" );
document.write( " Lesson | \n" );
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document.write( "6.Write an equation of the line that passes through the given two points \n" );
document.write( "( -2 , 7 ), ( 4 , -23 ) \r \n" );
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document.write( " Solved by pluggable solver: Finding the Equation of a Line | \n" );
document.write( "First lets find the slope through the points ( , ) and ( , ) \n" );
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document.write( " Start with the slope formula (note: ( , ) is the first point ( , ) and ( , ) is the second point ( , )) \n" );
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document.write( " Plug in , , , (these are the coordinates of given points) \n" );
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document.write( " Subtract the terms in the numerator to get . Subtract the terms in the denominator to get  \n" );
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document.write( " Reduce \n" );
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document.write( " So the slope is \n" );
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document.write( "Now let's use the point-slope formula to find the equation of the line: \n" );
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document.write( " ------Point-Slope Formula------ \n" );
document.write( " where is the slope, and ( , ) is one of the given points \n" );
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document.write( " So lets use the Point-Slope Formula to find the equation of the line \n" );
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document.write( " Plug in , , and (these values are given) \n" );
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document.write( " Rewrite as  \n" );
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document.write( " Distribute  \n" );
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document.write( " Multiply and to get . Now reduce to get  \n" );
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document.write( " Add to both sides to isolate y \n" );
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document.write( " Combine like terms and to get \n" );
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document.write( " Answer: \n" );
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document.write( " So the equation of the line which goes through the points ( , ) and ( , ) is: \n" );
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document.write( " The equation is now in form (which is slope-intercept form) where the slope is and the y-intercept is  \n" );
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document.write( " Notice if we graph the equation and plot the points ( , ) and ( , ), we get this: (note: if you need help with graphing, check out this solver) \n" );
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document.write( " Graph of through the points ( , ) and ( , ) \n" );
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document.write( " Notice how the two points lie on the line. This graphically verifies our answer. \n" );
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