School Students Algebra Quadratics
Difference of two squares Common Factors
The difference of two squares
The difference of two squares is exactly that one squared term take away another squared term. Remember a squared term is a term multiplied by itself.
Examples:
x2 – 16 = ( x x x) – (4 x 4)
49 – y2 = (7 x 7) – (y x y)
1 – y2 = (1 x 1) – (y x y)
x2 – y2 = ( x x x) – (y x y)
This is how you factorise the difference of two squares
a2 – b2 = (a + b) (a – b)
Expanding the bracket, click here for a reminder
(a + b) (a – b) = (a x a) – (a x b) + (b x a) – (b x b)
= a2 – ab + ab – b2 ( – ab + ab = 0 )
= a2 – b2
