MATH 1002 Lecture one Cheat Sheet by foxxer

Binomial Products are expres­sions which involve multip­lying two term expres­sions by each other. USE FOIL METHOD.
If both binomial terms are the same
for example (2x+y)­(2x+y) we may write it as (2x + y)²
We may remember the formula for these expres­sions as:
(a + b)² = a² + 2ab + b²
(a−b)² = a² −2ab + b²
We can now simplify an example such as
(2x + 2y)² + (x−2y)² = 4x² + 8xy + 4y² + x² −4xy + 4y²
= 5x² + 4xy + 8y²
Sum Times The Difference
We should notice that when we expand an expression such as (3x+2y­)(3­x−2y) we get a special result.
(3x + 2y)(3x−2y) = 9x² −6xy + 6xy−4y²
= 9x² −4y
So We Have A Special Rule
(a+b) (a-b) = a² - b²