substitution method

[sarahtbkh]

I am near tears here because I cannot figure out how to solve by substitution. Please help me solve the following.

3m + n = 2
m - 3n = 4

What is the solution to the problem. Solve by typing an ordered pair.

Another one is that I need to solve by useing the substitution method is....

5x + 3y = -4
-6x + y = 37

I have tried everything but I am not even getting close to the answer.

 

[masters]

I am near tears here because I cannot figure out how to solve by substitution. Please help me solve the following.

3m + n = 2
m - 3n = 4

What is the solution to the problem. Solve by typing an ordered pair.

Another one is that I need to solve by useing the substitution method is....

5x + 3y = -4
-6x + y = 37

I have tried everything but I am not even getting close to the answer.

Hi sarahtbkh,

Hold back those tears. Substitution method says to solve one of the equations for a particular variable. Then substitute it into the other equation.

[1] \(\displaystyle 3m+n=2\)
[2] \(\displaystyle m-3n=4\)

Let's solve for n in equation [1].

[1] \(\displaystyle n=2-3m\)

Now, let's substitute for n in [2].

[2] \(\displaystyle m-3(2-3m)=4\)

\(\displaystyle m-6+9m=4\)

\(\displaystyle 10m=10\)

\(\displaystyle \boxed{m=1}\)

Finally, substitute this value back into \(\displaystyle n=2-3m\) to find n.

Apply this same technique to your second problem. I would probably solve the second equation for y.