1. `mx + my = m(x + y)`
2. `x^2 - y^2 = (x - y)(x + y)`
3. `x^3 - y^3 = (x - y)(x^2 + xy + y^2)`
4. `x^3 + y^3 = (x + y)(x^2 - xy + y^2)`
5. `(x + y)^2 = x^2 + 2xy + y^2`
6. `(x - y)^2 = x^2 - 2xy + y^2`
7. `(x + y)^3 = x^3 + y^3 + 3xy(x + y)`
8. `(x - y)^3 = x^3 - y^3 - 3xy(x - y)`
9. `(x + y + z)^2 = x^2 + y^2 + z^2 + 2xy + 2yz + 2zx`
This material is intended as a summary. Use your textbook for detail explanation.
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