In which order do you teach graphing, elimination and substitution? Does it matter which order they are taught in?

How do you introduce solving simultaneous equations? Which problem do you use? Is it devoid of context?

What prior learning needs to be re-capped or mastered before starting with any of these techniques? How do you ensure this is retrieved and fluid? i.e. adding and subtracting negative algebraic terms for elimination, gradients of straight lines for graphing, etc. Would you re-cap in starters? homework tasks? full lessons?

See the applet below. Would you have students explore solutions graphically as an independent/collaborative task, would you lead a discussion with this applet, or would you simply not use it?