# Pre-Calc

Solve the system of equations using either the substitution method or the multiplication/addition method

3x+2y=14
2x-4y=4

1. 👍
2. 👎
3. 👁
1. I would double the first then add that to the 2nd to get
8x = 32
x =4
sub into the first:
12 + 2y = 14
2y = 2
y = 1

x=4, y =1

check by subbing those values into both equations, they should work

1. 👍
2. 👎
2. thanks so much! do you know how i could check the solution by writing the system as a matrix equation and using the inverse matrix?

1. 👍
2. 👎
3. Wow , that would be overkill, but anyway ....

first of all , it is very difficult to write it in matrix form in this format,
so you would have the matrix
3 2
2-4 multiplied by the column matrix
x
y
=
14
4

I will assume you know how to find the inverse of a 2by2 matrix, and how to multiply matrices
the inverse of our 2by2 is
1/4 1/8
1/8 -3/16

so
1/4 1/8
1/8 -3/16
multiplied by
14
4
gives us
4
1

1. 👍
2. 👎
4. ahh thank you and sorry for the overkill

1. 👍
2. 👎

## Similar Questions

1. ### How do I do this.?(Math.)

Use the Substitution method to solve the system of equations. y - 2x = -5 3y - x = 5 Solve one of the equations for x or y. Let's solve the first one for y: y - 2x = -5 y = 2x - 5 Now let's substitute 2x - 5 for y in the second

What advantages does the method of substitution have over graphing for solving systems of equations? Choose the correct answer below. A. Graphing cannot be used to solve dependent or inconsistent systems due to the nature of the

3. ### Algebra

When is the substitution method a better method than graphing for solving a system of linear equations?

4. ### Math

1. Explain the advantages and disadvantages of both the substitution method and the elimination method for solving a system. Help please. The only reasons I can think of is because in substitution it might be more difficult cause

1. ### Substitution Method

Use the Substitution method to solve the system of equations. x + y = -4 x - y = 2 x + y = -4 x - y = 2 In the second equation, x= y+2 Putting that in the first.. (y+2) + y= -4 subtract two from each side, then divide each side by

2. ### Substitution Method in Algebra!HELP PLZ!

Use the Substitution method to solve the system of equations. 3x + y = 5 4x - 7y = -10 multiply first equation by 4 multiply second equation by 3 thus both equations have same x or y value in this case it is the x value. 12x + 4y

3. ### Algebra

Explain why the addition method might be preferred over the substitution method for solving the system 2x-3y=5 5x+2y=6

4. ### math plz help ;-;

1. Solve the system by any method: 2x-5y=-1 2x-y=1 How many solutions does the system of equations below have? Explain your answer. y=3/5x-1 y=6/10x+3 plz help me ;-; i don't understand how to do this, sorry ;-;

1. ### Math

Solve the following system of equations using the cross multiplication method,ax+by=a-b;bx-ay=a+b

2. ### algebra

o Systems of equations can be solved by graphing or by using substitution or elimination. What are the pros and cons of each method? Which method do you like best? Why? o What circumstances would cause you to use a different

3. ### Algebra

Using the substitution method, what is the value of a in the solution to the system of equations below? a=3b+7 4a+9b=70

4. ### Algebra

When solving a system of equations by the addition method, how do you know when the system has no solution?