text: what are the methods to solve an equation with more than one variable? first i would like to know how to solve equations that both have x, and y.i've managed before with help, but forgotten. then, maybe examples of equations with 3 variables? i am sure such an equation is present in higher algebra and precalculus, and whatnot, but i'm curious.if anyone gives an example, how would the rules differ for a system of solving equations? here is the rule: you have to have the same number of equations as you have variables to solve.  for example:  x + y = 1  x - y = 1  here you have two equations and two unknowns.  the process is to solve one equation for one of the variables, and substituting that into the other:  x = 1 - y  (1-y) -y = 1  now you solve the new equation for y:  -2y = 0 y = 0  now you plug y into any of the equations (preferably the easier one), and you get x.  x + 0 = 1  x = 1  of course this gets more complicated with each new variable and equation, but the process is the same.  you keep substituting until you get one equation with one variable.