Key learning points

1. You can use your knowledge of changing the subject to rewrite one or both equations.
2. If one of the variables is the subject, the equivalent expression can be substituted into the other equation.
3. This is another method that involves reducing the number of variables.

Common misconception

Keywords

• Elimination - Elimination is a technique to help solve equations simultaneously and is where one of the variables in a problem is removed.

• Substitution - Substitute means to put in place of another. In Algebra, substitution can be used to replace variables with values, terms, or expressions.

• Subject (equation/formula) - The subject of an equation/a formula is a variable that is expressed in terms of other variables. It should have an exponent of 1 and a coefficient of 1