She’s right—using simultaneous equations does get really complicated, and if you’d like to send me your work for the solution, I’d love to see it. But the system is also kind of a trick. Like a sudoku ...

Okay, so I know that as soon as someone tells me what method to use, I'm gonna instantly remember it, but right now, I can think of only 1 way to solve simultaneous equations, and that doesn't work so ...