M6 · Advanced
Algebra
Difference of two squares
Formula
a^2 - b^2 = (a - b)(a + b)
Rule
A square subtracted from a square factorises into a product of a difference and a sum.
Example
x^2 - 9 = (x - 3)(x + 3)
Tip
Recognise any term written as something squared.
Learn this concept
Algebraic expressions