# How do you solve #x + y = -4# and #y = -3x + 2# using substitution?

##### 2 Answers

#### Explanation:

Given equations are

Substitute the second equation to the first equation

divide both sides of the equation by

Use the second equation and

God bless....I hope the explanation is useful.

#### Explanation:

Let's make

The substitution method means that you will take an equation and plug it into another one to get rid of an unknown.

These questions may sometimes require you to rearrange one of the equations first, so that there is only one variable* on one side of the equation.

In this case, that won't be necessary as equation 2 is already in this form. There is only the variable y on the left side.

Now, you can look at equation 1 and ask yourself where you can plug equation 2 into.

We can see that the y can be replaced with -3x+2 since they are both equal.

Now we know that

Conclusion:

# A variable is a number we don't know yet which is represented by a letter such as x or y.