Literal Equations and Word Problems

-2 = 4r + s solve for s.

• s = -2 + 4r

• s = 2 - 4r

• s = -2 - 4r

• s = 2 + 4r

A - B = C

(solve for A)

• A = C - B

• A = C + B

• A - C = B

• B = A - C

• Subtract 5x from both sides

• Add 5x to both sides

• Add 7 to both sides

• Subtract 10 from both sides

• Subtract 3

• Subtract 7 from both sides

• Add 7 to both sides

• Distribute the 3

Two types of memberships are available for a water park.

1. An unlimited use membership for $70 per month

2. A monthly $10 fee plus $5.00 per visit

Which equation represents find the number of visits, v, per month needed for the two membership types to cost the same amount?

• 10v + 5 = 70v

• 10 + 5v = 70v

• 10 + 5v = 70

• 10v + 5 = 70

Target was having a NO-TAX sale on DVDs and other select electronics. Donovin found a bin labeled “DVDs—$2.50 each!” and decided to buy a bunch of his favorite movies from this bin. Donovin also decided to buy a DVD player for $49.99. If his total came out to be $67.49, which equation could be used to find out how many DVDs, d, he bought?

• 2.50d + 67.49 = 49.99

• 2.50 + 49.99d = 67.49d

• 2.50 = 67.49d - 49.99d

• 2.50d + 49.99 = 67.49

Two phone companies offer different pay-as-you-go plans (data sold separately):

1: $0.05 per minute talking plus $20 per month for unlimited texting.

2. $0.10 per minute talking plus $12 per month for unlimited texting.

Which equation represents the number of minutes, m, you would have to talk for the two plans to cost the same amount?

• 0.05m + 20 = 0.10m + 12

• 0.05 + 20m = 0.10m + 12m

• 0.05m + 0.10m = 20 + 12

• 0.05m - 20 = 0.10m - 12

Two phone companies offer different pay-as-you-go plans (data sold separately):

1: $0.05 per minute talking plus $20 per month for unlimited texting.

2. $0.10 per minute talking plus $12 per month for unlimited texting.

If you plan on choosing one of these plans for one month while you study abroad, what variable might you define?

• m = the number of months

• d = how much data you will use

• t = number of texts you will send

• m = number of minutes you will talk

Penelope is going to the carnival to ride the rides. It costs $20 to get into the carnival and ride tickets are $0.50 each. Write an equation that represents this scenario if she spends $35 in all.

• .50x + 20 = 35
• .50x = 35
• .50 + 20x = 35 
• .50x - 20 = 35

Scott works on cars. He charges $35 for each car plus $7 per hour. Write an equation that represents this scenario if Kylie's car bill was $63.

• 7x + 35 = 63
• 7x = 63
• 7x - 35 = 63
• 35x + 7 = 63