All Common Core: 8th Grade Math Resources
Example Questions
Example Question #13 : How To Find The Solution For A System Of Equations
Solve the set of equations:
Solve the first equation for :
Substitute into the second equation:
Multiply the entire equation by 2 to eliminate the fraction:
Using the value of , solve for :
Therefore, the solution is
Example Question #14 : How To Find The Solution For A System Of Equations
Solve the following system of equations:
Set the two equations equal to one another:
2x - 2 = 3x + 6
Solve for x:
x = -8
Plug this value of x into either equation to solve for y. We'll use the top equation, but either will work.
y = 2 * (-8) - 2
y = -18
Example Question #321 : Equations / Inequalities
Solve this system of equations for :
None of the other choices are correct.
Multiply the bottom equation by , then add to the top equation:
Divide both sides by
Example Question #11 : Solve Systems Of Two Linear Equations: Ccss.Math.Content.8.Ee.C.8b
Solve the following system of equations:
no solution
infinitely many solutions
When we add the two equations, the variables cancel leaving us with:
Solving for we get:
We can then substitute our value for into one of the original equations and solve for :
Example Question #322 : Equations / Inequalities
Solve the following system of equations.
We are given
We can solve this by using the substitution method. Notice that you can plug from the first equation into the second equation and then get
Add to both sides
Add 9 to both sides
Divide both sides by 5
So . We can use this value to find y by using either equation. In this case, I'll use .
So the solution is
Example Question #173 : Expressions & Equations
Use algebra to solve the following system of linear equations:
There are a couple of ways to solve a system of linear equations: graphically and algebraically. In this lesson, we will review the two ways to solve a system of linear equations algebraically: substitution and elimination.
Substitution can be used by solving one of the equations for either or , and then substituting that expression in for the respective variable in the second equation. You could also solve both equations so that they are in the form, and then set both equations equal to each other.
Elimination is best used when one of the variables has the same coefficient in both equations, because you can then use addition or subtraction to cancel one of the variables out, and solve for the other variable.
For this problem, elimination makes the most sense because our variables have the same coefficient. We can add our equations together to cancel out the
Next, we can divide both sides by to solve for
Remember, when we are solving a system of linear equations, we are looking for the point of intersection; thus, our answer should have both and values.
Now that we have the value of , we can plug that value into the variable in one of our given equations and solve for
We want to subtract from both sides to isolate the
Our point of intersection, and the solution to the two system of linear equations is
Example Question #13 : Solve Systems Of Two Linear Equations: Ccss.Math.Content.8.Ee.C.8b
Use algebra to solve the following system of linear equations:
There are a couple of ways to solve a system of linear equations: graphically and algebraically. In this lesson, we will review the two ways to solve a system of linear equations algebraically: substitution and elimination.
Substitution can be used by solving one of the equations for either or , and then substituting that expression in for the respective variable in the second equation. You could also solve both equations so that they are in the form, and then set both equations equal to each other.
Elimination is best used when one of the variables has the same coefficient in both equations, because you can then use addition or subtraction to cancel one of the variables out, and solve for the other variable.
For this problem, elimination makes the most sense because our variables have the same coefficient. We can subtract our equations to cancel out the
Next, we can divide both sides by to solve for
Remember, when we are solving a system of linear equations, we are looking for the point of intersection; thus, our answer should have both and values.
Now that we have the value of , we can plug that value into the variable in one of our given equations and solve for
We want to add to both sides to isolate the
Then we divide each side by
Our point of intersection, and the solution to the two system of linear equations is
Example Question #14 : Solve Systems Of Two Linear Equations: Ccss.Math.Content.8.Ee.C.8b
Use algebra to solve the following system of linear equations:
There are a couple of ways to solve a system of linear equations: graphically and algebraically. In this lesson, we will review the two ways to solve a system of linear equations algebraically: substitution and elimination.
Substitution can be used by solving one of the equations for either or , and then substituting that expression in for the respective variable in the second equation. You could also solve both equations so that they are in the form, and then set both equations equal to each other.
Elimination is best used when one of the variables has the same coefficient in both equations, because you can then use addition or subtraction to cancel one of the variables out, and solve for the other variable.
For this problem, elimination makes the most sense because our variables have the same coefficient. We can subtract our equations to cancel out the
Next, we can divide both sides by to solve for
Remember, when we are solving a system of linear equations, we are looking for the point of intersection; thus, our answer should have both and values.
Now that we have the value of , we can plug that value into the variable in one of our given equations and solve for
We want to subtract from both sides to isolate the
Then divide both sides by to solve for
Our point of intersection, and the solution to the two system of linear equations is
Example Question #213 : Grade 8
Use algebra to solve the following system of linear equations:
There are a couple of ways to solve a system of linear equations: graphically and algebraically. In this lesson, we will review the two ways to solve a system of linear equations algebraically: substitution and elimination.
Substitution can be used by solving one of the equations for either or , and then substituting that expression in for the respective variable in the second equation. You could also solve both equations so that they are in the form, and then set both equations equal to each other.
Elimination is best used when one of the variables has the same coefficient in both equations, because you can then use addition or subtraction to cancel one of the variables out, and solve for the other variable.
For this problem, elimination makes the most sense because our variables have the same coefficient. We can subtract our equations to cancel out the
Next, we can divide both sides by to solve for
Remember, when we are solving a system of linear equations, we are looking for the point of intersection; thus, our answer should have both and values.
Now that we have the value of , we can plug that value into the variable in one of our given equations and solve for
We want to subtract from both sides to isolate the
Then divide both sides by to solve for
Our point of intersection, and the solution to the two system of linear equations is
Example Question #177 : Expressions & Equations
Use algebra to solve the following system of linear equations:
There are a couple of ways to solve a system of linear equations: graphically and algebraically. In this lesson, we will review the two ways to solve a system of linear equations algebraically: substitution and elimination.
Substitution can be used by solving one of the equations for either or , and then substituting that expression in for the respective variable in the second equation. You could also solve both equations so that they are in the form, and then set both equations equal to each other.
Elimination is best used when one of the variables has the same coefficient in both equations, because you can then use addition or subtraction to cancel one of the variables out, and solve for the other variable.
For this problem, elimination makes the most sense because our variables have the same coefficient. We can subtract our equations to cancel out the
Next, we can divide both sides by to solve for
Remember, when we are solving a system of linear equations, we are looking for the point of intersection; thus, our answer should have both and values.
Now that we have the value of , we can plug that value into the variable in one of our given equations and solve for
We want to subtract from both sides to isolate the
Our point of intersection, and the solution to the two system of linear equations is