Expanding brackets means removing the brackets by multiplying each term inside the bracket by the factor outside the bracket.
Expanding Single Brackets
When expanding a single bracket, multiply each term inside the bracket by the number or variable outside the bracket.
\[3(x + 5)\]
Multiply both terms inside the bracket by the 3 on the outside.
\[3 \times x + 3 \times 5 = 3x + 15\]
Expanding Double Brackets
For expanding double brackets, multiply each term in the second bracket by each term in the first.
\[(x + 3)(x + 4) = x(x + 4) + 3(x + 4)\]
\[x(x + 4) + 3(x + 4) = x^2 + 4x + 3x + 12\]
Then collect the like terms.
\[x^2 + 4x + 3x + 12 = x^2 + 7x + 12\]
Expanding Triple Brackets
Always focus on expanding two brackets at a time. When these brackets are expanded, then multiply each term by each term in the third bracket.