College Algebra : Solving Equations and Inequallities

Study concepts, example questions & explanations for College Algebra

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Example Questions

Example Question #9 : Linear Equations

Solve for .

Possible Answers:

Correct answer:

Explanation:

First distribute out each side of the equation.

 simplifies to .

Now for the right hand side, 

 becomes .

Now we equate both sides.

,

Example Question #10 : Linear Equations

Solve for .

Possible Answers:

Correct answer:

Explanation:

First, we need to simplify what's inside the parentheses. 

Now we continue to evaluate the left hand side.

The right hand side does not need any reduction.

We set the two sides equal to each other.

Example Question #11 : Linear Equations

Solve the equation:  

Possible Answers:

Correct answer:

Explanation:

In order to isolate the x-variable, we will need to multiply both sides by one third.

Simplify both sides.

The answer is:  

Example Question #11 : Solving Equations And Inequallities

Evaluate:  

Possible Answers:

Correct answer:

Explanation:

Add  on both sides.

Add one on both sides.

Divide by 16 on both sides.

The answer is:  

Example Question #11 : Solving Equations And Inequallities

Express the following linear inequality in interval notation.

Possible Answers:

Correct answer:

Explanation:

Upon solving for x, we find that x is less than or equal to 3.  The left-hand term of the interval is negative infinity since any number less than 3 is in our set, and infinity always has a parenthesis around it.  The right-hand term of the interval is 3 since it is the upper bound of our set.  There is a bracket around it because 3 is included in our set (3 is less than or equal to 3).  Remember when dividing or multiplying by a negative number in an inequality to reverse the direction of the inequality.

Example Question #11 : Solving Equations And Inequallities

Solve:

Possible Answers:

Correct answer:

Explanation:

Step 1: Subtract 6 from both sides...

Step 2: Divide by 2.

Simplify:

Example Question #11 : Solving Equations And Inequallities

Solve: (positive roots only)

Possible Answers:

Correct answer:

Explanation:

Step 1: Subtract  from both sides

Step 2: Simplify:

Step 3: Divide..

Step 4: Take the square root of both sides...

Step 5: Simplify and get the answer...

 

Example Question #16 : Linear Equations

Solve:

Possible Answers:

Correct answer:

Explanation:

Move  to the other side by subtracting it from both sides.

Simplify:

Divide by the coefficient, the number in front of x.

Reduce:

Example Question #1 : Equations With More Than One Variable

Solve for X:

 

Possible Answers:

 

Correct answer:

Explanation:

In , if we're solving for x, we first need to get the "x" term isolated. We do this by subtracting 3 from both sides so:

becomes

Now we divide both sides by 8

Re-written the answer becomes

 

Example Question #1 : Equations With More Than One Variable

Larry has a handful of dimes and quarters. In total, he has 14 coins with a value of $2.60. How many of each coin does he have?

Possible Answers:

6 Dimes

8 Quarters

7 Dimes

7 Quarters

10 Dimes

4 Quarters

8 Dimes

6 Quarters

9 Dimes

5 Quarters

Correct answer:

6 Dimes

8 Quarters

Explanation:

Since this problems has 2 variables (D-dimes and Q-quarters) we need 2 equations. Because Larry has 14 coins, the first equation can be written as:

 

 

The value of those coins equals $2.60 or 260 cents. If Dimes are worth 10C and quarters are 25C, the next equation can be written as

 

To solve this write both equations on top of each other

 

 

 

Now we eliminate 1 variable by multiplying 1 equation by the lowest common denominator (as a negative) and adding the equations together.

  becomes

adding the equations

   

-----------------------------------

                 

 

now we solve for Q.

Since we know Q, now we plug it back in to an equation and find D

 

 

Larry has 6 dimes and 8 quarters

 

 

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