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AS Mathematics. Algebra – Manipulation of brackets. Objectives. Be confident in the use of brackets Be able to factorise linear expressions. Review of expanding brackets. multiply term by term. collect like terms. Alternatives for expanding (x + 3)(x + 5). grid method. smiley face. x 2.
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AS Mathematics Algebra – Manipulation of brackets
Objectives • Be confident in the use of brackets • Be able to factorise linear expressions
Review of expanding brackets multiply term by term collect like terms
Alternatives for expanding (x + 3)(x + 5) grid method smiley face x2 +5x +3x +15
Perfect square! Remember (a + b)2 = a2 + 2ab + b2
Difference of 2 squares! Remember (a-b)(a+b)= a2 - b2
– A harder one! multiply term by term collect like terms
Example 5 multiply any two brackets multiply remaining bracket collect like terms
Factorising This involves taking out any common factors. Try to spot the HCF by inspection.
(i) common factors The HCF of 12x & 18y is 6 Check your answer by expanding the brackets The HCF of 6x2 & 21x is 3x
(ii) grouping The first two terms have common factor a, the last two have common factor y There is now a common factor of (x + y) Check your answer by expanding the brackets.
To illustrate this:- let z = x + y but z = x + y …..as before!
The first two terms have common factor x, the last two have common factor 3 There is now a common factor of (y + 2) Check your answer by expanding the brackets.
For this method to succeed, both brackets should be the same, i.e both (1 - y) Check your answer by expanding the brackets