Page 57 - 新思维数学学生用书7 样章

2 Expressions, formulae and equations

2 Write these statements as inequalities. The first one has been done

for you.
a y is greater than 8 y > 8
b n is greater than −1
c p is less than zero
d q is less than −2

3 Copy each number line and show each inequality on the number line.

a x > 3 1 2 3 4 5 6

b x < 5 2 3 4 5 6 7

c x > −3 –6 –5 –4 –3 –2 –1

d x < −1 –4 –3 –2 –1 0 1

4 Write down the inequality that each of these number lines shows.
Use the letter x.

a b
0 1 2 3 4 6 7 8 9 10

c d
–2 –1 0 1 2 –7 –6 –5 –4 –3
5 This is part of Katya’s homework.

Tip
Question
Given the inequality x > 7, write down: In the solution to
i the smallest integer that x could be part ii, the three
ii a list of the integer values that x could be. dots (called
ellipses) after
Solution the number 11
i The smallest integer is 7. show that the list
ii x could be 7, 8, 9, 10, 11, … goes on forever.

a Explain the mistakes that Katya has made and write down the
correct solutions.
b Discuss your answers to part a with a partner.
Make sure you have corrected all of Katya’s mistakes.

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