1. Bellwork Solve the following equations for y
1) 2y – 4x = 10 3) -x – 3y + 9 = 0
2) 12x – 6y = 18
Answers: 1) y = 2x + 5
2) Y = -1/3 x + 3
3) Y = 2x - 3

2. Test Review – 9.1 Solve a linear system by graphing.
1.The lines intersect and there is one solution to both equations! The solution is an ordered pair (x, y).
2. The lines are parallel, and there is no solution.
3. The lines are consistent and dependent, they are the same line. Infinite solutions.
You will be asked to solve systems by graphing, and your graph must be correct!

3. 9.5 Solve linear systems of inequalities
The solutions of a system of linear inequalities are ALL the coordinate pairs that make all the inequalities in the system true.
Graph and shade the solution set to both inequalities. The overlapping area is the solution set. Be prepared to give examples of solutions, and nonsolutions.

4. 9.2 Solve a linear system by substitution.
Solve an equation for one variable. Choose the easiest one to solve for!
Substitute that expression (value) into the other equation and solve.
Use that value to go back and plug it into either original equation to find other variable.

5. 9.3 and 9.4 Elimination
Add or subtract the equations to eliminate one variable.
Multiple the equations if you need to so that adding or subtracting will eliminate a variable.
Solve for the remaining variable, then plug that into an original equation and solve for the other variable.

6. 9.1 - Let’s try one… Solve the system by graphing…. 2x – y = -5
( you may know several ways to find the solution, but you will need to graph the system when asked!)
Answer: (-1, 3)

7. Answer:
y = 10x + 20
y = 11x + 15
Solution is (5, 70)

8. Solve by substitution
y = -2x + 6
3y – x + 3 = 0
Solution (3, 0)

9. Solution: (4.5, 0.5)
Page 282 #9

10. Page 301 # 12
Answer: 2L + 2W = 120
L – 2W = 24 Solution: L = 48ft ; W = 12 ft

11. Sharon has some one-dollar bills and some five-dollar bills
Sharon has some one-dollar bills and some five-dollar bills. She has 14 bills. The value of the bills is $30. Solve a system of equations using elimination method to find how many of each kind of bill she has.
Answer:
x + y = 14
x + 5y = 30
Solution: $1 Bill = 10; $5 Bill = 4

12. Which ones are the same in each of the following sets of equations?
#1. a)2y = 2x + 4
b) -4y = -2x + 8
c) y = x + 2
d) y – 2 = x
#2. a)4x – 4y > 8
b) y < x – 2
c) -40x + 40y > 80
Answer:
Rewrite all equations and Inequalities as y = mx + b
#1 Equations a, c and d are same
#2 Inequalities a and b are same

13. Write and graph the system linear inequalities. (page 318 #11)
Answer:
a) W ≥ 10
2L + 2W ≤ 72
b) Possible lengths 1 to 20
Possible widths 10 to 35
c) Any width <10
Any Length > 20

14. Solve by elimination 6x + 5y = 39 3x + 5y = 27 Answer:
Simply Subtract the two equations.
Solution.(4, 3)

15. Inequalities:
x + y ≤ 20
8x + 10y ≥ 120
Answer: Let
x = Grocery Store Hours
y = Lawn Mowing Hours
Graph the two inequalities and pick a solution from the overlapping region of the shaded areas