Page 99 - MAT KS3 Y8 Cambridge CheckPoint

9.1 Collecting like terms

✦ Exercise 9.1

1 Use the guidelines opposite to rewrite these expressions.
a 8 × n b 4 + m c h8 d 5fe e 2b + 5a f −3d + 5
g 4 + 2 × v h 6 × k × j i p × 2 + m6 j −2a + 5c k −4qp + 3 l −3yx − 8ba

2 Look at this set of cards.

2 × n + m2 2 + n2 2 × n × n
−2 + 2n

2
n × 2
n × 2 + 2 2 × n − 2 × 1
−2 + 2 × n × m
2n + 2
2m + 2n 2
2n n2 − 2

a Put the cards into groups of expressions that have the same meaning.
b i Write down the expression on the card that is left over.
ii Simplify the expression on the card that is left over.

3 Simplify each expression.
a 6x + 4x + 3x b 8y − 2y + 5y c 7z − z − 9z
d 2a + 4b + 6a − 3b e 8c − 4d − 3c + d f 2ab + 4ba − 3ba
g 3cd + 4de + 7dc − 2ed h 4 + 9v − 6v − 11 i 5t − 3u − 8t + 10u
2
2
2
2
2
j 4x + 3x + 8x − 2x k 11y − 3y − 5y 2 l a + 2a + 2 − a + 5a
4 In an algebraic pyramid you find the expression in each block by adding the expressions in the two
blocks below it. Copy and complete this pyramid.
5a − b + 6b − 2a
= 5a − 2a + 6b − b
3a + 5b = 3a + 5b
3b + 2a 3a + 4b 5a − b 6b − 2a

5 Copy and complete this algebraic pyramid.

3cd − 8ef
4cd − 4ef
cd − 8ef 7cd + ef

6 This is part of Zalika’s homework.
She has made several mistakes. Question Simplify: 1. 8ab – ab + 2ac
2
2
a Explain what she has done 2. 3x + 4xy – 2x – yx
2
wrong. Answer 1. 8ab – ab + 2ac = 7ab + 2ac = 9a bc
2
2
2
b Work out the correct answers. 2. 3x + 4xy – 2x – yx = x + 4xy – yx
9 Simplifying expressions and solving equations 97