Equations that have more than one unknown can have an infinite number of solutions. For example, \(2x + y = 10\) could be solved by: \(x = 1\) and \(y = 8\) \(x = 2\) and \(y = 6\) \(x = 3\) and \(y = ...

Simultaneous equations like 𝒚 = 2𝒙 - 1 and 𝒚 = 𝒙 + 1 can be represented graphically. To solve the equations graphically, the two lines 𝒚 = 𝒙 + 1 and 𝒚 = 2𝒙 - 1 are drawn on the same diagram.

"Even the +, −, =, and x signs we take for granted only came into widespread use in the 17th century. Which means that the earlier algebraists we know of … all had expressed their equations mostly in ...