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

9-1

6 -7

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 -1B) Multiply the second equation by -1C) Multiply the first equation by -5D) Multiply the second equation by -5

If you want to solve this system of equations by adding, which of the following represent

the correct steps?

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?

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?

Solving 3x3 Systems:(1)The graph of the solution set of an equation in

threevariables 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:

Last Practice

Problem