Common Core: 8th Grade Math : Expressions & Equations

Study concepts, example questions & explanations for Common Core: 8th Grade Math

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Example Questions

Example Question #131 : Expressions & Equations

Select the option that describes the solution(s) for the following equation:

 

Possible Answers:

Infinitely many solutions 

No solution

One solution 

Correct answer:

One solution 

Explanation:

Let's begin by discussing our answer choices:

In order for an equation to have no solution, the equation, when solved, must equal a false statement; for example, 

In order for an equation to have one solution, the equation, when solved for a variable, but equal a single value; for example, 

In order for an equation to have infinitely many solutions, the equation, when solved, must equal a statement that is always true; for example,  

To answer this question, we can solve the equation:

This equation equals a single value; thus, the correct answer is one solution.  

Example Question #132 : Expressions & Equations

Select the option that describes the solution(s) for the following equation:

Possible Answers:

One solution 

Infinitely many solutions 

No solution

Correct answer:

Infinitely many solutions 

Explanation:

Let's begin by discussing our answer choices:

In order for an equation to have no solution, the equation, when solved, must equal a false statement; for example, 

In order for an equation to have one solution, the equation, when solved for a variable, but equal a single value; for example, 

In order for an equation to have infinitely many solutions, the equation, when solved, must equal a statement that is always true; for example,  

To answer this question, we can solve the equation:

This equation equals a statement that is always true; thus, the correct answer is infinitely many solutions.  

 

Example Question #133 : Expressions & Equations

Solve for :

Possible Answers:

Correct answer:

Explanation:

can be simplified to become

Then, you can further simplify by adding 5 and  to both sides to get .

Then, you can divide both sides by 5 to get .

Example Question #4 : Systems Of Equations

Solve for :

Possible Answers:

Correct answer:

Explanation:

To solve for , you must first combine the 's on the right side of the equation. This will give you .

Then, subtract  and from both sides of the equation to get .

Finally, divide both sides by  to get the solution .

Example Question #134 : Expressions & Equations

Solve for :

Possible Answers:

Correct answer:

Explanation:

First, combine like terms within the equation to get 

.

Then, add  and subtract  from both sides to get 

.

Finally, divide both sides by  to get the solution of .

Example Question #15 : How To Find The Solution To An Equation

Solve for .

Possible Answers:

Cannot be determined

Correct answer:

Explanation:

Subtract x from both sides of the second equation.

Divide both sides by  to get .

Plug in y to the other equation.

  

Divide 10 by 5 to eliminate the fraction, yielding .

Distribute the 2 to get .

Add  to each side, and subtract 15 from each side to get .

Divide both sides by 7 to get , which simplifies to .

Example Question #171 : Grade 8

Solve for :

Possible Answers:

Correct answer:

Explanation:

Combine like terms on the left side of the equation:

Use the distributive property to simplify the right side of the equation:

Next, move the 's to one side and the integers to the other side:

Example Question #3 : Solve Linear Equations With Rational Number Coefficients: Ccss.Math.Content.8.Ee.C.7b

Solve for :

Possible Answers:

Correct answer:

Explanation:

First. combine like terms to get

.

Then, add  and subtract from both sides to separate the terms.

This gives you .

Finally, divide both sides by  to get a solution of .

Example Question #1 : Solve Linear Equations With Rational Number Coefficients: Ccss.Math.Content.8.Ee.C.7b

Solve for :

Possible Answers:

None of the other answers

Correct answer:

Explanation:

First, you must multiply the left side of the equation using the distributive property.

This gives you .

Next, subtract  from both sides to get .

Then, divide both sides by  to get .

Example Question #2 : Solve Linear Equations With Rational Number Coefficients: Ccss.Math.Content.8.Ee.C.7b

Solve for 

 

Possible Answers:

Correct answer:

Explanation:

In order to solve for , we need to isolate the  to one side of the equation. 

For this problem, we need to multiply each side by 

Next, we need to subtract  from each side:

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