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Matrices-and-determiminant/619641: Use cramer rule to solve ..
x + y + z =12
x - y = 2
x - z = 4 1 solutions
Answer 389751 by ewatrrr(10682) on 2012-06-11 07:46:16 (Show Source):
You can put this solution on YOUR website!
Hi, Previously Posted
| Solved by pluggable solver: Using Cramer's Rule to Solve Systems with 3 variables |

First let . This is the matrix formed by the coefficients of the given system of equations.
Take note that the right hand values of the system are , , and and they are highlighted here:

These values are important as they will be used to replace the columns of the matrix A.
Now let's calculate the the determinant of the matrix A to get . To save space, I'm not showing the calculations for the determinant. However, if you need help with calculating the determinant of the matrix A, check out this solver.
Notation note: denotes the determinant of the matrix A.
---------------------------------------------------------
Now replace the first column of A (that corresponds to the variable 'x') with the values that form the right hand side of the system of equations. We will denote this new matrix (since we're replacing the 'x' column so to speak).

Now compute the determinant of to get . Again, as a space saver, I didn't include the calculations of the determinant. Check out this solver to see how to find this determinant.
To find the first solution, simply divide the determinant of by the determinant of to get: 
So the first solution is 
---------------------------------------------------------
We'll follow the same basic idea to find the other two solutions. Let's reset by letting again (this is the coefficient matrix).
Now replace the second column of A (that corresponds to the variable 'y') with the values that form the right hand side of the system of equations. We will denote this new matrix (since we're replacing the 'y' column in a way).

Now compute the determinant of to get .
To find the second solution, divide the determinant of by the determinant of to get: 
So the second solution is 
---------------------------------------------------------
Let's reset again by letting which is the coefficient matrix.
Replace the third column of A (that corresponds to the variable 'z') with the values that form the right hand side of the system of equations. We will denote this new matrix

Now compute the determinant of to get .
To find the third solution, divide the determinant of by the determinant of to get: 
So the third solution is 
====================================================================================
Final Answer:
So the three solutions are , , and giving the ordered triple (6, 4, 2)
Note: there is a lot of work that is hidden in finding the determinants. Take a look at this 3x3 Determinant Solver to see how to get each determinant.
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Matrices-and-determiminant/619643: Use Cramer rule to solve.
x + y + z = 12
x - y = 2
x - z = 4 1 solutions
Answer 389750 by ewatrrr(10682) on 2012-06-11 07:43:59 (Show Source):
You can put this solution on YOUR website!
Hi,
| Solved by pluggable solver: Using Cramer's Rule to Solve Systems with 3 variables |

First let . This is the matrix formed by the coefficients of the given system of equations.
Take note that the right hand values of the system are , , and and they are highlighted here:

These values are important as they will be used to replace the columns of the matrix A.
Now let's calculate the the determinant of the matrix A to get . To save space, I'm not showing the calculations for the determinant. However, if you need help with calculating the determinant of the matrix A, check out this solver.
Notation note: denotes the determinant of the matrix A.
---------------------------------------------------------
Now replace the first column of A (that corresponds to the variable 'x') with the values that form the right hand side of the system of equations. We will denote this new matrix (since we're replacing the 'x' column so to speak).

Now compute the determinant of to get . Again, as a space saver, I didn't include the calculations of the determinant. Check out this solver to see how to find this determinant.
To find the first solution, simply divide the determinant of by the determinant of to get: 
So the first solution is 
---------------------------------------------------------
We'll follow the same basic idea to find the other two solutions. Let's reset by letting again (this is the coefficient matrix).
Now replace the second column of A (that corresponds to the variable 'y') with the values that form the right hand side of the system of equations. We will denote this new matrix (since we're replacing the 'y' column in a way).

Now compute the determinant of to get .
To find the second solution, divide the determinant of by the determinant of to get: 
So the second solution is 
---------------------------------------------------------
Let's reset again by letting which is the coefficient matrix.
Replace the third column of A (that corresponds to the variable 'z') with the values that form the right hand side of the system of equations. We will denote this new matrix

Now compute the determinant of to get .
To find the third solution, divide the determinant of by the determinant of to get: 
So the third solution is 
====================================================================================
Final Answer:
So the three solutions are , , and giving the ordered triple (6, 4, 2)
Note: there is a lot of work that is hidden in finding the determinants. Take a look at this 3x3 Determinant Solver to see how to get each determinant.
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logarithm/619673: Write thhis expression as a single logarithm.
2(log(a)n - 4log(a)m)
the logs have the a below them, couldn't figure out of to show them like that, but help in how to solve this problem would be very much appreciated. 1 solutions
Answer 389744 by ewatrrr(10682) on 2012-06-11 07:30:31 (Show Source):
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Length-and-distance/619663: find the length of the sides of tiangle whose vertices are (1,4),(-4,0),(3,-3).Classify the triangle 1 solutions
Answer 389736 by ewatrrr(10682) on 2012-06-11 07:14:59 (Show Source):
You can put this solution on YOUR website!
Hi,
find the length of the sides of tiangle whose vertices are
(1,4),
(-4,0) D = sqrt(4^2 + 5^2) = sqrt(41)
(3,-3 D = sqrt(3^2 + -7^2) = sqrt(58) longest side C
(1,4), D = sqrt(-7^2 + 2^2) = sqrt(53)
41 + 53 = 94 > 58
If A, B and C are the sides of a triangle where C is the longest side, then we can say the following
i) If A^2+B^2 = C^2 is true, then we have a right triangle
ii) If A^2+B^2 > C^2 is the case, then we have an acute triangle.*****
iii) If A^2+B^2 < C^2, then we have an obtuse triangle.
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Quadratic-relations-and-conic-sections/619477: I have the following equation: I need to identify the vertices and foci of the hyperbola. I also need to show my work.
(y+5)^2/36 - (x+2)^2/25 =1
thank you 1 solutions
Answer 389681 by ewatrrr(10682) on 2012-06-10 18:41:37 (Show Source):
You can put this solution on YOUR website!
Hi,
Note:Standard Form of an Equation of an Hyperbola opening up and down is:
where Pt(h,k) is a center with vertices 'b' units up and down from center and foci from center along x = h
(y+5)^2/36 - (x+2)^2/25 =1 C(-5,-2) V(,-5,-8) & V(-5,4), F(-5, -2± )
See below descriptions of various conics
Standard Form of an Equation of a Circle is
where Pt(h,k) is the center and r is the radius
Standard Form of an Equation of an Ellipse is where Pt(h,k) is the center. (a positioned to correspond with major axis)
a and b are the respective vertices distances from center and ± are the foci distances from center: a > b
Standard Form of an Equation of an Hyperbola opening right and left is:
where Pt(h,k) is a center with vertices 'a' units right and left of center and foci {{sqrt(a^2+b^2) from center along y = k.
Standard Form of an Equation of an Hyperbola opening up and down is:
where Pt(h,k) is a center with vertices 'b' units up and down from center along x = h.
the vertex form of a parabola opening up or down, where(h,k) is the vertex.
The standard form is , where the focus is (h,k + p)
the vertex form of a parabola opening right or left, where(h,k) is the vertex.
The standard form is , where the focus is (h +p,k )
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Subset/619442: If x1 = - 2; x2 = 5; y1 = 3; y2 = - 7, find the value of: (y2 - y1) / (x2 - x1)
a. 10 / 7;
b. - 10 / 3;
c. 4 / 9;
d. - 10 / 7 1 solutions
Answer 389661 by ewatrrr(10682) on 2012-06-10 15:17:13 (Show Source):
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