Factor  common  to  all terms:  A   factor  common  to  all the terms   of  a
polynomial  can be  factored    out.    This    is  essentially the distributive    property    in
reverse.    For example,    all three   terms   in  the polynomial   3 x^3  +   12x^2   –   6x  contain
a   factor  of  3x. Pulling out the common  factor  yields   3 x(x^2    +   4x  –   2).
Difference  of  squares:    You will    want    to  be  especially  keen    at  spotting
polynomials in  the form    of  the difference  of  squares.    Whenever    you have    two
identifiable    squares with    a   minus   sign    between them,   you can factor  the
expression  like    this:
a^2     –   b^2     =   (a  +   b)(a    –   b)For example, 4 x^2 – 9 factors to (2x + 3)(2x – 3).
Squares of  binomials:  Learn   to  recognize   polynomials that    are squares of
binomials:
For example,     4 x^2  +   12x +   9   factors to  (2x +   3)^2 ,  and a^2     –   10a +   25  factors to  (a  –
5)^2.
CLASSIC FACTORABLES
Factor  common  to  all terms
Difference  of  squares
Square  of  a   binomial