Writing and solving real-world linear equations

Writing and solving real-world linear equations

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Objective: By the end of the lesson, we will write and solve real-world linear equations.

Real world example

I bought 2 bags of gummy worms for $4.50. Write an equation to represent this situation.

2g = 4.50

A number decreased by 8 is 12

• is means =

• "A number decreased by 8" tells us that a number we don't know should be subtracted by 8

• x - 8 =

• The words after the word is, tells us what should be on the right side of the equation. So 12 should be on the right side of the equation.

• x - 8 = 12

Multiple Choice

1. Ted bought a dolphin poster for $12.  He now has $5.  Which choice models this situation?

• m - 12 = 5
• m - 5 = 12
• m + 5 = 12
• m + 12 = 5

Multiple Choice

Which choice models this situation?
Robyn had some video games, then bought 4 more.  Now she has a total of 10 games.

• v - 4 = 10
• v + 4 = 10
• 10/4 = v
• 4v = 10

Multiple Choice

5.  After dropping 5ºF, the temperature was 37ºF.  Which choice models this situation?

• d - 37 = 5
• d + 5 = 37
• d - 5 = 37
• d + 37 = 5

Multiple Choice

Which equation shows the number of bottles left after x days?

A family buys a case of water with 48 bottles and drinks 5 bottles per day.

• y = 48x + 5

• y = -5 + 48x

• y = -5x - 48

• y = 48 - 5x

Multiple Choice

After paying $5.12 for a salad, Kamauri has $27.10. How much money did he have before buying the salad?

• n + $5.12 = $27.10
• n - $5.12 = $27.10
• n - $5.12 = -$27.10
• $5.12 - n = $27.10

Multiple Choice

For lunch, Amanda had a hamburger and some potato chips. The hamburger totaled 325 calories and each chip had 12 calories. Write a linear equation to represent the situation.

• y = 12 + 325

• y = 12x + 325

• y = 325 - 12x

• y = 325x + 12

Multiple Choice

For a field trip 4 students rode in cars and the rest filled nine buses. How many students were in each bus if 472 students were on the trip?

• 4x=472

• 9x=472

• 4+9x=472

• 4+x=472

Multiple Choice

The drama club sold tickets to a play for $5 each. They also made $55 in soda and popcorn sales. If the drama club made a total of $290, how many tickets were sold?

• 47

• 58

• 69

• 113

Multiple Choice

Billy's car needed repairs. The mechanic charged him $140 for the parts and an additional $48 an hour for labor. How many hours of labor did the mechanic work on the car if her total bill was $260?

• 3 hours

• 12 hours

• 2.5 hours

• 5 hours

Fill in the Blank

During the summer, you work 30 hours per week at a gas station and earn $8.75 per hour. You also work as a landscaper for $11 per hour and can work as many hours as you want. You want to earn a total of $400 per week. How many hours must you work as a landscaper?

Multiple Choice

Which choice models this situation?

Last week, Tina worked 35 hours in 5 days. She worked the same number of hours each day. How many hours did she work each day?

• h - 5 = 35

• h + 5 = 35

• 5h = 35

• h/5 = 35

Draw

Marcus needs to sell 25 tickets to a fundraiser by Friday. So far, he has sold 9 tickets. Write an equation that shows how many tickets he still needs to sell.

Multiple Choice

Tara caught three times as many fish this year than last year. She caught 63 fish by the end of the year. Which equation represents how many fish she caught last year?

• 3y = 63

• 3 + y = 63

• 63 - y = 3

• y/3 = 63

Multiple Choice

Which choice models this situation?

Anna participated in a read-a-thon. Mr. Cole pledged $4 per book and gave Anna $44. How many books did Anna read?

• b - 4 = 44

• b + 4 = 33

• 4b = 44

• b/4 = 44

Poll

How do you feel about this topic?

• I will never understand this

• I am getting there, with more practice

• I am in a good spot

• I am an expert