Factoring identities
d
Difference of squares
The difference of squares of quantities is equal to the product of their sum and difference.
$(1).\,\,$ $a^2-b^2$ $\,=\,$ $(a+b)(a-b)$
$(2).\,\,$ $x^2-y^2$ $\,=\,$ $(x+y)(x-y)$
Sum of cubes
$(1).\,\,$ $a^3+b^3$ $\,=\,$ $(a+b)(a^2+b^2-ab)$
$(2).\,\,$ $x^3+y^3$ $\,=\,$ $(x+y)(x^2+y^2-xy)$
Difference of cubes
$(1).\,\,$ $a^3-b^3$ $\,=\,$ $(a-b)(a^2+b^2+ab)$
$(2).\,\,$ $x^3-y^3$ $\,=\,$ $(x-y)(x^2+y^2+xy)$
