Page 47 - 新思维数学学生用书8 样章

2 Expressions, formulae and equations

Exercise 2.4

1 Copy and complete these factorisations. 2 3 4 5
All the numbers you need are in the cloud.

a 3x + 15 = 3(x + ) b 10y−15 = 5(2y − )

c 14 − 28x = 7( − 4x) d 12−9y = 3(
−3y)

2 Copy and complete these factorisations. 1 2 5 7
All the numbers you need are in the cloud.
a 4x + 5x = x(4x + ) b 6xy + 12y = 6y(x + )
2
c 7y−7y = 7y( d 21x−12xy = 3x(
−y)
−4y)
2

Think like a mathematician
3 In pairs or a small group, discuss what Marcus and Arun say.

I don’t, I get
When I factorise 6(x + 3), so one of
6x + 18, I get us must be
3(2x + 6). wrong!

Do you agree with Arun? Explain your answer.

4 Factorise each of these expressions.

Each one has a highest common factor of 2.
a 2x + 4 b 4b − 6
c 8 + 10y d 18 − 20m
5 Factorise each of these expressions.

Each one has a highest common factor of 3.
a 18 + 21p b 3y − 18
c 9 + 15m d 12 − 27x
6 Factorise each of these expressions.

Make sure you use the highest common factor.
a 10z + 5 b 8a − 4
c 14 + 21x d 18 − 24z

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