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Example Questions
Example Question #2 : Augmented Matrices
When solving a system of three linear equations in three variables using the Gauss-Jordan elimination method, your initial augmented matrix is as follows:
Which of the following is notation for the next step you should perform?
When applying the Gauss-Jordan method to solve a three-by-three linear system, the objective is to use row operations to form an augmented matrix of the form
,
with the solution of the system.
Once the initial augmented matrix
is set up, the first step should always be to get a 1 in the upper left position; this is usually done by multiplying every element in Row 1 by the reciprocal of the first element in that row. Since the element in that position is , every element in Row 1 is multiplied by reciprocal . This step can be written using the notation .
Example Question #7 : Augmented Matrices
Use augmented matrices to solve the following system of equations:
Begin by constructing an augmented matrix for our system of equations:
Switch rows 1 and 2:
Add row 2 and twice row 1, to row 1:
Divide row 1 by 5:
Subtract 3 times row 1, from row 2:
Divide row 2 by 2:
Solution:
Plug the respective values of x and y into both equations to verify the solution:
Example Question #7 : Augmented Matrices
Use augmented matrices to solve the following system of equations:
Construct an augmented matrix for our system of equations:
Swap rows 1 and 3:
Subtract 2 times row 1 from row 2:
Subtract row 1 from row 3:
Add row 2 and three times row 3, to row 3:
Divide row 3 by 10:
Add row 3 to row 1:
Subtract row 3 from row 2:
Divide row 2 by 3:
Solution:
Plug the respective values of x, y, and z into all equations to verify the solution:
Example Question #1 : Non Linear Systems
Solve the following system of equations
There are no Real Solutions
First lets solve equation 2 for y.
Now we plug in into equation 1.
FOIL the left hand side, simplify and then subtract from each side.
Now use the quadratic equation in order to solve for .
Recall the quadratic formula
, where refer to the coefficients in the quadratic equation .
So the solutions for x are as follows
Now we just plug these values of x into equation 2 to solve for y.
So the solutions to these pair of equations are:
Example Question #2 : Non Linear Systems
Solve the system of equations to find the points where the graphs of the equations intersect.
,
,
,
,
,
,
Solve the system of equations,
(1)
(2)
Notice that we can multiply both sides of equation (2) by to obtain,
(3)
Now equate equations (3) and (4) to obtain,
This is a quadratic equation, rearrange to find the roots by setting to zero and factoring,
Use these values to find the corresponding values of by substituting into either of the original equations. Using equation (1),
The points and are the intersection points of the two functions,
Example Question #3 : Non Linear Systems
Solve the following system of equations:
Subtract the second equation from the first, to eliminate the y terms:
-
This yields the following:
Factor out an x from both terms:
Solve for x:
Plug in the values for x into the first equation:
Therefore, when , , and when ,
Plug in the values for x and y to make sure they satisfy the second equation too:
Solution:
Example Question #2 : Non Linear Systems
Solve the following system of equations:
Substitute the value of x from the second equation, into the first equation:
Subtract y from both sides of the equation:
Use the quadratic formula to solve for y:
or
Plug the first value of y into the first equation:
Re-write the equation to make it easier to solve for x:
Add to each side of the equation:
The second value of y into the first equation:
Re-write the equation to make it easier to solve for x:
Add to each side of the equation:.
Plug the values of x and y into the second equation to make sure they satisfy both of them:
Solution:
Example Question #3 : Non Linear Systems
Solve the following system of equations:
Multiply the second equation by 6, to eliminate the denominator:
Simplify:
Plug the value of y, from the first equation, into the second equation:
Simplify:
Simplify further:
Use the quadratic formula to solve for x:
or
Plug the first value of x into the first equation:
Plug the second value of x into the first equation:
Plug the values of x and y into the second equation to make sure they satisfy both of them:
Solution:
Example Question #2 : Non Linear Systems
Solve the following system of equations:
Substitute the value of y from the second equation, into the first equation:
Subtract x from both sides of the equation:
Use the quadratic formula to solve for x:
or
Plug the first value of x into the second equation:
Plug the second value of x into the second equation:
or
Verify the first solution by plugging the first values of x and y into both equations:
Verify the second solution by plugging the second values of x and y into both equations:
Solution: