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Tuesday, 22 March 2011
Wednesday, 2 March 2011
Simplifying Expressions
Collecting like terms
When simplifying algebraic expressions, you can only add terms that a like (the same)
Examples:
b + b + b = 3b
a + b + a + b = 2a + 2b
5w + 3w = 8w
y + y2 + 2y2 = y + 3y2
Friday, 25 February 2011
Equations and Formulae
Difference between equations and formulae
An equation contains unknown quantities; for example,
3x + 2 = 11.
This equation can be solved to determine x.
A formula links one quantity to one or more other quantities; for example,
C = 2πr
The formula can be used to determine C for any given value or r
Thursday, 24 February 2011
Ask Questions on Algebra
Ask any questions you may have on algebra
Please post your questions and I'll reply asap.
Please post your questions and I'll reply asap.
Factorising
Factorising
Factorising (put in brackets) can be said to be the 'opposite of expanding brackets'.
To factorise an expression live 3w+12 you find out the highest factor the terms have in common.
In this case it is 3. That means 3 needs to be outside the bracket.
Then you find out what you multiply by 3 to get 3w and what you multiply by 3 to get 12.
3 x w = 3w and 3 x 4 = 13 since 3 is the highest factor both terms have in common.
so factorising 3x+12 gives 3(w+4).
Examples:
Factorise the following expressions
1) 4y + 12
The highest common factor is 4, so 4 has to be outside the bracket.
4 x y = 4y and 4 x 3 = 12
so 4y + 12 = 4(y + 3)
2) 30b + 42
The highest common factor is 6, so 6 has to be outside the bracket.
6 x 5b = 30b and 6 x 7 = 42
so 30b + 42 = 6(5b + 7)
3) 6v + 15w
The highest common factor is 3, so 3 has to be outside the bracket.
3 x 2v = 6v and 3 x 5w = 15w
s0 6v + 15w = 3(2v + 3w)
Factorising (put in brackets) can be said to be the 'opposite of expanding brackets'.
To factorise an expression live 3w+12 you find out the highest factor the terms have in common.
In this case it is 3. That means 3 needs to be outside the bracket.
Then you find out what you multiply by 3 to get 3w and what you multiply by 3 to get 12.
3 x w = 3w and 3 x 4 = 13 since 3 is the highest factor both terms have in common.
so factorising 3x+12 gives 3(w+4).
Examples:
Factorise the following expressions
1) 4y + 12
The highest common factor is 4, so 4 has to be outside the bracket.
4 x y = 4y and 4 x 3 = 12
so 4y + 12 = 4(y + 3)
2) 30b + 42
The highest common factor is 6, so 6 has to be outside the bracket.
6 x 5b = 30b and 6 x 7 = 42
so 30b + 42 = 6(5b + 7)
3) 6v + 15w
The highest common factor is 3, so 3 has to be outside the bracket.
3 x 2v = 6v and 3 x 5w = 15w
s0 6v + 15w = 3(2v + 3w)
Expanding Brackets
Expanding or multipying out brackets.
To expand a bracket such as 3(x +2) you multiply every term in the bracket by 3 making it 3x + 6.
Examples
Expand these brackets:
1) 4(y + 3) = 4y + 12
2) 6 (5b + 7) = 30b + 42
3) 3 (2v + 5w) = 6v + 15w
To expand a bracket such as 3(x +2) you multiply every term in the bracket by 3 making it 3x + 6.
Examples
Expand these brackets:
1) 4(y + 3) = 4y + 12
2) 6 (5b + 7) = 30b + 42
3) 3 (2v + 5w) = 6v + 15w
Wednesday, 24 March 2010
Spot the mistake
Spot the mistake:
3(x + 5) = 3x + 5
4(xy + y) = 4x + 4y
7(w - 4) = 7w + 28
6(a + 2) = 6a + 12
6a + 7a + 2b = 15ab
3(x + 5) = 3x + 5
4(xy + y) = 4x + 4y
7(w - 4) = 7w + 28
6(a + 2) = 6a + 12
6a + 7a + 2b = 15ab
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