Simultaneous Equations Summary
If we are given one equation with two unknowns, there are an infinite number of possible solutions to them.
Two different equations involving two unknown variables are required to find a unique solution to them both.
To solve two equations at the same time (so called simultaneous equations) we first rearrange one equation for one variable; substitute this in the other equation; solve for one variable then substitute in the other equation.
To solve for 3 unknowns, we require at least 3 separate equations.
To solve for n unknowns (where n is a positive integer!), we require at least n separate equations.