Expansion and Factorisation....

To change the form of algebraic expressions to make it simpler or more complicated, expansion and factorisation can be done.
A factorised form of algebraic expression should have brackets. Factorisation means pulling out the common factors and putting them into brackets. Example, 2x +6 = 2(x+3), 21y +3 =3(7y+1).
Expansion is the exact opposite of factorisation. While factorisation is putting in brackets, expansion is removing the brackets. To remove the brackets, the common factors are to be multiplied to the numbers in the brackets. Example, 2(x+3) = 2x +6, 3(7y +1) = 21y +3.
However, this method of factorisation and expansion is only applicable to algebraic expressions as quadratic equations hv more coefficients and powers of variables which makes it hard to factorise. Factorisation and expansion of quadratic equation can only be done using the cross method or special identities.