ABSTRACT
At the end of this chapter, you should be able to:
• solve simultaneous equations in two unknowns by substitution • solve simultaneous equations in two unknowns by elimination • solve simultaneous equations involving practical situations • solve simultaneous equations in three unknowns
Only one equation is necessarywhenfinding the value of a single unknown quantity (as with simple equations in Chapter 11). However, when an equation contains two unknown quantities it has an infinite number of solutions. When two equations are available connecting the same two unknown values then a unique solution is possible. Similarly, for three unknown quantities it is necessary to have three equations in order to solve for a particular value of each of the unknown quantities, and so on. Equations which have to be solved together to find the unique values of the unknown quantities, which are true for each of the equations, are called simultaneous equations.
