Theory
Expanding brackets means removing the brackets by multiplying every term inside the bracket by the term outside.
A term is a separate part of an expression, such as 2x or 3. In 4(2x + 3), both 2x and 3 must be multiplied by 4.
After expanding, simplify by collecting like terms. x terms combine with x terms, number terms combine with number terms.
If the multiplier outside the bracket is negative, it changes the sign of every term inside the bracket.
For Edexcel method marks, show the expansion before collecting like terms. Do not jump straight to an answer if signs are involved.
Key rulea(b + c) = ab + ac