1. Bellwork Solve the following by: y = 2x y = x + 3 1.) Graphing
2.) Substitution
3.) Linear Combination (+)
Show all your Work

2. To be able to write a linear system word problem and solve it.
Today’s Objective
To be able to write a linear system word problem and solve it.

3. Example #1
Read example 2 on page 368 and find the two items that were sold in the problem and the total sold.
Style A shoes
Style B shoes

4. Example #1 Let Style A = x Let Style B = y Total sold = 240 So….
x + y = 240 (1st Equation)

5. Example #1 Total Receipts = 17,652 So….
Receipts for Style A = 66.95x
Receipts for Style B = 84.95y
Total Receipts = 17,652 So….
66.95x y = 17,652 (2nd Equation)

6. Solve by Substitution x + y = 240 66.95x + 84.95y = 17,652
x + y = 240 (Solve for x)
x + y - y = y
x = y

7. Solve by Substitution x = 240 - y 66.95x + 84.95y = 17,652
66.95(240-y) y = 17652

8. Solve by Substitution 18y = 1584 (divide by 18) y = 88 Now Find x
y = (subtract 16068)
18y = 1584 (divide by 18)
y = 88
Now Find x

9. Solve by Substitution Since y = 88 and x = 240 - y then x = 240 - 88
Style A = 152, Style B = 88

10. Steps
#1 ~ Make a list and pick the variables
#2 ~ Write the equations
#3 ~ Solve

11. Example #2
Read example 3 on page 369 and find the two missing items in the problem.
Total Earnings
Total Sales

12. Example #2 Step #1 Let Total Sales = x Let Total Earnings = y Step #2
y = 20, x (1st job)
y = 15, x (2nd job)

13. Solve by (L.C. add) y = 20,000 + .01x y = 15,000 + .02x
y = 20, x (times by -1)
-y = x
y = x (add)
You Finish to find x

14. Solve by (L.C. add) y = 20,000 + .01x y = 15,000 + .02x
y = 20, x (times by -1)
-y = x
y = x (add)
0 = x

15. Solve by (L.C. add) 0 = -5000 + .01x 0+5000=-5000+5000+.01x
5000 = .01x (divide by .01)
500,000 = x
You must sell $500,000 in supplies for both jobs to be equal in salary.

16. Solve by (L.C. add) y = 20,000 +.01(500000) y = 20,000 + 5,000
What salary would you earn?
Since y = 20, x &
x = 500,000 then
y = 20, (500000)
y = 20, ,000
y = 25,000

17. Classwork
Do page 370 (7,9,10)
#8 extra credit