Exercise 1 Page 247

We are told that the equations $y=3x-20$ and $y=\text{-}2x+10$ intersect at $(6,\text{-}2).$ We need to figure out, without solving, the solution to the equation What can we notice about this new equation? Most importantly, it is made of the right-hand sides of the previous equations. Since we know that the point of intersection for the original two equations is $(6,\text{-}2),$ we know that Finally, since the left-hand sides are the same, we know that the right-hand sides must also be equal. Therefore, making the solution to our equation $x=6.$