How do you solve #x^2+y^2=109# and #x-y= - 7# using substitution?
These roots satisfy the given eqns.
Now substitute "
Expand the bracket:
Collect like terms:
subtract 109 from both sides:
Now put these two values into
So the answers are:
Express the implicit relation in terms of one variable only. See method below.
You have two equations:
You can express
Using this substitution we can write
This will give us a quadratic expression where we can solve for
Simplifying this we get:
This can be factorized to
We can then solve for
Note that  implies
Expanding and simplifying the left side of 
Converting to standard polynomial form by subtracting