Math Equations and Inequalities

Refer to the previous question. On a number line, show all the values of t that make your inequality true. Which statement best describes your number line?

• The graph shows an open circle at 4.5 with shading to the right.

• The graph shows an open circle at 4.5 with shading to the left.

• The graph shows an open circle at -4.5 with shading to the right.

• The graph shows an open circle at -4.5 with shading to the left.

Answer explanation

The temperature will reach -4 degrees C after 4.5 hours.

Since the temperature needs to be colder, t must be larger than 4.5.

Lin got a $50 gift card to an online music store. She uses the gift card to buy an album for $9.99. She also wants to use the gift card to buy some songs. Each song costs $1.29. Which of these inequalities describes this situation, where n is the number of songs Lin wants to buy?

Answer explanation

The $1.29 per song is added to the amount being spent on the gift card.

Lin can spend the entire $50 or less than what is on the card, but she cannot spend more than $50.

At midnight, the temperature in a city was 5 degrees Celsius. The temperature was dropping at a steady rate of 2 degrees Celsius per hour. Write an inequality that represents t, the number of hours past midnight, when the temperature was colder than -4 degrees Celsius.

Answer explanation

The temperature starts at 5 and decreases 2 degrees every hour, so 2t should be subtracted from 5.

We want this quantity to be less than -4 degrees.

Match the graph with its inequality.

• 11 < a

• 11 > a

• 11 ≤ a

• 11 ≥ a

Solve:
8m - 9 > 71

• m > 10

• m > 1

• m < 1

• m > -48

Which expression is equivalent to 3x + 5 + 7x + 2?

• 10x + 7

• 17x

• 17

• 15x + 2

Which expression is equivalent to 6(3y - 2y + 7)?

• 18y + 7

• 21y - 14y + 7

• 18y + 42

• 6y + 42

Evaluate 3b + 4c if b = 9 and c = 3

• 27

• 12

• 15

• 39

Evaluate the following expression

x² -2(x+5) if x=10

• 10

• 70

• 85

• 90

Does the given value make the inequality true?  x + 9 > 21, when x = 15

• True

• Not True