Page 30 - 新思维数学活动用书7 样章

2.3 Collecting like terms

Challenge

11 This is part of Maddi’s homework.

Question

Write these expressions in their simplest form.
a 2x + 8 + 7x – 4 b 5rg + 4t – t + 2gr
Solution

a 2x + 8 = 10x, 7x – 4 = 3x, 10x + 3x = 13x
b 5rg + 4t – t + 2gr = 5rg + 4 + 2gr

Maddi has made several mistakes. Explain the mistakes Maddi has made.
12 Copy and complete this algebraic pyramid.
Remember, you find the expression in each block by adding the

expressions in the two blocks below it.

17a + 11b
8a + 6b
5a + 2b
2a + b

13 Simplify these expressions. Write your answers in their simplest form.

a 3a − a b b + b 3 c 3c + c
4 2 5 10 7
14 In this diagram, the expressions in each rectangle simplify to the expression in the circle.

1 Tip

Remember:
4 3
x × y = xy, so

2 8ab 2 2x × y = 2xy and
4x × 3y = 12xy.
3 4

1
a Copy and complete the diagram in two different ways.

b Is it possible to say how many ways there are to complete the diagram? Explain your answer.

29