How do you solve #x + y = -4# and #y = -3x + 2# using substitution?
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.
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
# A variable is a number we don't know yet which is represented by a letter such as x or y.