Algebra 1 : Functions and Lines

Study concepts, example questions & explanations for Algebra 1

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Example Questions

Example Question #15 : How To Find The Next Term In An Arithmetic Sequence

Find the next term in the following arithmetic sequence:

Possible Answers:

Correct answer:

Explanation:

First, find the common difference for the sequence. Subtract the first term from the second term.

Subtract the second term from the third term.

To find the next value, add  to the last given number.

Example Question #16 : How To Find The Next Term In An Arithmetic Sequence

Find the next term in the arithmetic sequence:  

Possible Answers:

Correct answer:

Explanation:

The terms are in decreasing order, and to determine how much each number is decreasing by, we will subtract first term with the second term and the second term with the third term.

Subtract the first and second term.

Subtract the second and the third term.

Notice that each term is subtracted by five.

Subtract the third term by five to get the next term.

The answer is .

Example Question #12 : How To Find The Next Term In An Arithmetic Sequence

Find the next term in the following sequence.

Possible Answers:

None of the other answers.

Correct answer:

Explanation:

The two things we need to find out are HOW the sequence changes (adddition, subtraction, multiplication, division, etc.) and by WHAT factor.

Start by finding the difference between the first two terms.

Now let's find the difference between the 2nd and 3rd given term.

Based on these two points, we can infer that this sequence changes by adding 13 to the previous term. Therefore...

the next term in the sequence is 22.

Example Question #2 : Proportionalities

If an object is hung on a spring, the elongation of the spring varies directly as the mass of the object. A 20 kg object increases the length of a spring by exactly 7.2 cm. To the nearest tenth of a centimeter, by how much does a 32 kg object increase the length of the same spring?

Possible Answers:

Correct answer:

Explanation:

Let  be the mass of the weight and the elongation of the spring. Then for some constant of variation 

We can find  by setting  from the first situation:

so 

In the second situation, we set  and solve for :

 

which rounds to 11.5 centimeters.

Example Question #1 : Identifying Variable Relationships

 varies directly with the square root of . If , then  . What is the value of  if ?

Possible Answers:

None of these answers are correct.

Correct answer:

Explanation:

If  varies directly with the square root of , then for some constant of variation

If , then ; therefore, the equation becomes 

or

.

Divide by 5 to get , making the equation 

.

If , then .

Example Question #201 : Functions And Lines

If an object is hung on a spring, the elongation of the spring varies directly with the mass of the object. A 33 kilogram object increases the length of a spring by exactly 6.6 centimeters. To the nearest tenth of a kilogram, how much mass must an object posess to increase the length of that same spring by exactly 10 centimeters?

Possible Answers:

Correct answer:

Explanation:

Let  be the mass of the weight and the elongation of the spring, respectively. Then for some constant of variation 

.

We can find  by setting :

Therefore .

Set  and solve for :

 kilograms

Example Question #5 : Proportionalities

If  is directly proportional to  and when  at , what is the value of the constant of proportionality?

 

Possible Answers:

Correct answer:

Explanation:

The general formula for direct proportionality is

where  is the proportionality constant. To find the value of this , we plug in  and

Solve for  by dividing both sides by 12

So .

Example Question #3492 : Algebra 1

The amount of money you earn is directly proportional to the nunber of hours you worked. On the first day, you earned $32 by working 4 hours.  On the second day, how many hours do you need to work to earn $48.

Possible Answers:

Correct answer:

Explanation:

The general formula for direct proportionality is 

where  is how much money you earned,  is the proportionality constant, and  is the number of hours worked.

Before we can figure out how many hours you need to work to earn $48, we need to find the value of . It is given that you earned $32 by working 4 hours. Plug these values into the formula

Solve for  by dividing both sides by 4.

So . We can use this to find out the hours you need to work to earn $48. With , we have

Plug in $48.

Divide both sides by 8

So you will need to work 6 hours to earn $48.

Example Question #3493 : Algebra 1

The volume of a fixed mass of gas varies inversely as the atmospheric pressure, as measured in millibars, acting on it, and directly as the temperature, as measured in kelvins, acting on it.

A balloon is filled to a capacity of exactly 100 cubic meters at a time at which the temperature is 310 kelvins and the atmospheric pressure is 1,020 millibars. The balloon is released, and an hour later, the balloon is subject to a pressure of 900 millibars and a temperature of 290 kelvins. To the nearest cubic meter, what is the new volume of the balloon?

Possible Answers:

Correct answer:

Explanation:

If  are the volume, pressure, and temperature, then the variation equation will be, for some constant of variation ,

To calculate , substitute :

The variation equation is 

so substitute  and solve for 

Example Question #2 : Setting Up Equations

The monthly cost to insure your cars varies directly with the number of cars you own. Right now, you are paying $420 per month to insure 3 cars, but you plan to get 2 more cars, so that you will own 5 cars. How much does it cost to insure 5 cars monthly?

Possible Answers:

Correct answer:

Explanation:

The statement, 'The monthly costly to insure your cars varies directly with the number of cars you own' can be mathematically expressed as . M is the monthly cost, C is the number of cars owned, and k is the constant of variation.

Given that it costs $420 a month to insure 3 cars, we can find the k-value.

Divide both sides by 3.

Now, we have the mathematical relationship.

Finding how much it costs to insure 5 cars can be found by substituting 5 for C and solving for M.

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