Download A3 Factorizing and substitution

A3 Factorizing and
substitution
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Factorizing expressions
Some expressions can be simplified by dividing each term by
a common factor and writing the expression using brackets.
In the expression:
5x + 10
the terms 5x and 10 have a common factor, 5.
We can write the 5 outside of a set of brackets and mentally
divide 5x + 10 by 5.
(5x + 10) ÷ 5 = x + 2
This is written inside the bracket.
5(x + 2)
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Factorizing expressions
Writing 5x + 10 as 5(x + 2) is called factorizing the
expression.
Factorize 6a + 8
Factorize 12 – 9n
The highest common
factor of 6a and 8 is 2.
The highest common
factor of 12 and 9n is 3.
(6a + 8) ÷ 2 = 3a + 4
(12 – 9n) ÷ 3 = 4 – 3n
6a + 8 = 2(3a + 4)
12 – 9n = 3(4 – 3n)
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Pelmanism: Equivalent expressions
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Substitution
What does
substitution
mean?
In algebra, when we replace letters in an expression
or equation with numbers we call it substitution.
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Substitution
How can 4 + 3 ×
be written as an algebraic expression?
Using n for the variable we can write this as 4 + 3n.
We can evaluate the expression 4 + 3n by substituting
different values for n.
When n = 5
4 + 3n = 4 + 3 × 5
= 4 + 15
= 19
When n = 11
4 + 3n = 4 + 3 × 11
= 4 + 33
= 37
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Noughts and crosses – substitution
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