[tex]If\ y=3x+4\ and\ y=-x-4\ then\\\\3x+4=-x-4\qquad\text{subtract 4 from both sides}\\\\3x=-x-8\qquad\text{add x to both sides}\\\\4x=-8\qquad\text{divide both sides by 4}\\\\x=-2\\\\\text{put the value of x to the equation}\ y=-x-4\\\\y=-(-2)-4=2-4=-2\\\\Answer:\ \boxed{(-2,\ -2)}[/tex]
[tex]If\ y=10+6x\ and\ y=6x\ then\\\\10+6x=6x\qquad\text{subtract 6x from both sides}\\\\10=0\qquad FALSE\\\\Answer:\ \boxed{no\ solution}[/tex]
