Exercise 50 Page P21

Since neither equation has a variable with a coefficient of $1,$ we will use the Elimination Method. In this exercise, this means that either the $x\text{-}$terms or the $y\text{-}$terms must cancel each other out. Currently, none of the terms in this system will cancel out. Therefore, we need to find a common multiple between two variable like terms in the system. If we multiply (II) by $\text{-}6,$ the $x\text{-}$terms and $y\text{-}$terms will have opposite coefficients. We can see that the $x\text{-}$terms and $y\text{-}$terms will eliminate each other if we add (I) to (II). Solving this system of equations resulted in an identity; $0$ is always equal to itself.