For example, in the expression \(3(m + 7)\), multiply both \(m\) and 7 by 3, so: \(3(m + 7) = 3 \times m + 3 \times 7 = 3m + 21\). Expanding brackets involves using the skills of simplifying algebra.

KS3 Maths Expressions and formulae learning ... Learn what like and unlike terms are and simplify algebraic expressions by collecting like terms with this ... Changing the subject of a formula .