Expanding brackets (GCSE)
Single, double and triple brackets. Foundation does up to double; Higher includes triple.
Build up: single (a(b+c)), double ((a+b)(c+d)), triple (Higher: (a+b)(c+d)(e+f) by expanding two then the third). Use a grid, FOIL or systematic listing.
Worked examples
5(3x − 2) = 15x − 10.
(2x + 3)(x − 5) = 2x² − 7x − 15.
(x + 1)(x + 2)(x + 3) = (x + 1)(x² + 5x + 6) = x³ + 6x² + 11x + 6.
Frequently asked questions
FOIL or grid?
FOIL (First, Outer, Inner, Last) for double; grid scales better for triples.
Sign error?
Most common error in expanding. Track signs carefully when negatives appear.