Exercise 102 Page 530

1. Isolate a variable in one of the equations.
2. Substitute the expression for that variable into the other equation and solve.
3. Substitute this solution into one of the equations and solve for the value of the other variable.

For this exercise $y$ is already isolated in one equation, so we can skip straight to solving! Great! Now, to find the value of $y$ we need to substitute $x=2$ into either one of the equations in the given system. Let's use the second equation. The solution, or point of intersection, to this system of equations is the point $(2,\text{-}5).$

We can see that the $y\text{-}$terms will eliminate each other if we subtract (I) from (II). Now we can solve for $y$ by substituting the value of $x$ into either equation and simplifying. The solution, or point of intersection, of the system of equations is $(\text{-}3,\text{-}7).$