3. BACK How many liters of a 40% solutions must be mixed with 60 liters of a 80% solution to get a 70% solution? 20 liters

4. BACK In a chemistry class, 3 liters of a 4% silver iodide solution must be mixed with a 10% solution to get a 6% solution. How many liters of the 10% solution are needed? 1.5 liters

5. BACK Decide whether (-2, 1) is a solution to the system: 4x + y = -9 3x + 4y = -10 No

6. BACK Decide whether (-4, 2) is a solution to the system: 2x + y = -9 3x + 2y = -8 No

7. BACK Decide whether (-6, 1) is a solution to the system: x + y = -5 x - y = -7 Yes

8. BACK Solve for b. b = 2A/h

9. BACK Solve for b 1. b 1 = 2A/h − b 2

10. BACK Solve for s 3. S 3 = P − s 1 − s 2

11. BACK Walt made an extra $9000 last year from a part-time job. He invested part of the money at 8% and the rest at 7%. He made a total of $680 in interest. How much was invested at 7%? $4000

12. BACK Solve the system. (6, −4)

13. BACK Solve the system. −x – 3y = −23 6x + 3y = 33 (2, 7)

14. BACK Solve the system 7x – 7y = 91 2x + 3y = −9. (6, −7)

15. BACK Solve the system. (4/5, 1/7)

16. BACK Solve the system. 5x + 3y = 80 2x + y = 30 (10, 10)

17. BACK Solve the inequality. | z + 1 | > 0 [−1, ∞)

18. BACK Solve the inequality. | r + 4 | > 4 (− ∞, −8)  (0, ∞)

19. BACK Solve for x: | x | > 8 (− ∞, −8)  (8, ∞)

20. BACK Solve for x: | 7 – x | < 13 [−6, 20]

21. BACK Is the following an expression or an equation? X=15

22. BACK Is the following an equation or an expression? (y – 6) – (y – 3) = 7 Equation

23. BACK Is the following an expression or an equation? Expression

24. BACK Is the following an expression or an equation? 5(y + 6) + 6(y – 3) Expression

25. BACK After receiving a discount of 15.5% on its bulk order of printer toner, Best Office Supply pays $2197. What was the price of the order before the discount? $2600

26. BACK An investor bought 100 shares of stock. The value of the shares went up 7% and then he sold them. How much did the investor pay for the 100 shares if he sold them for $1284? $1200

27. BACK If 6 times a number is added to −4, the result is equal to 10 times the number. What is the number? The number is −1

28. BACK Solve the system. 4x − 8y = 24 x = 2y + 6 This is an dependent system. There are an infinite number of solutions.