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1.  Review Last Khan Academy Topic
Today
 Review Three Methods of Solving
 Solving 3 x 3 Systems of Equations
 CW 4.1-4.2 at or near Completion
 Grades will be completed Today
 Five Question Quiz

2. 9-1

3. 6 -7

5. Which of the following is a possible first step when
solving this system of equations by elimination?
5x + 2y = -1
x + 3y = -8
A) Multiply the first equation by -1
B) Multiply the second equation by -1
C) Multiply the first equation by -5
D) Multiply the second equation by -5

6. If you want to solve this system of equations by adding,
which of the following represent the correct steps?

7. Applying Systems of Equations:
Mrs. Smith took her family and friends to the movies.
There were a total of 12 people. Children tickets cost $5 and
adult tickets cost $10. She spent a total of $95. How many
adults & how many children went to the movies?

8. 1. Mark
the text.
2. Label
variables.
3. Create
equations.
4. Solve.
5. Check.
A restaurant charged one customer $28.20 for
3 small dishes and 5 large dishes and charged
another customer $23.30 for 4 small dishes
and 3 large dishes. What will 2 small and 4
large dishes cost?

9. Solving 3x3 Systems:(1)
The graph of the solution set of an equation in three
variables is a plane, not a line. In fact, graphing equations in
three variables requires the use of a three-dimensional
coordinate system. It is therefore, not practical to solve
3x3 systems by graphing
Solve the System: 4x + 2y - z = -5
3y + z = -1
2z = 10
1. Which is the easiest
variable to solve for?
2. Plug in where and solve
for what?
3. Substitute y and z values into equation 1; solve for x.
4. Substitute all values, check for equality.
5. The solution set is (1, -2, 5)
Solving 3x3 Systems: