year 8 maths

7E
Gradient–intercept form
425
Example 8
Example 9a
3 Write down the gradient and y -intercept for the graphs of these rules.
a y = 4x + 2 b y = 3x + 7 c y = 1 2 x + 1 d y = 2 3 x + 1 2
e y = −2x + 3 f y = −4x + 4 g y = −7x − 1 h y = −3x − 7
i y = −x − 6 j y = −1
2 x + 5 k y = −2
3 x − 1 2
l y = 3 7 x − 4 5
4 Find the rule for these graphs by first finding the values of m and b .
a
y
b
y
c
y
1 (1, 1)
x
−1
O
−1
1
(0, −1)
2
1
(2, 0)
−2 −1
O
−1
1 2
−2 (0, −2)
x
3 (0, 3)
2
(−1, 0)
1
−2 −1
O
−1
1 2
−2
x
d
y
e
y
f
y
(−5, 0)
−5 −4
5 (0, 5)
4
3
2
1
−3 −2 −1
O
−1
1
x
2
1
(0, 1)
(−1, −1) −1 O
−1
1
x
−2 −1
O
−1
1 2
(0, −1)
−2
−3
−4
−5
−6
(−2, −7)
−7
x
Example 9b
5 Find the rule for these graphs by first finding the values of m and b .
a
y
b
y
c
y
2 (0, 2)
1 (2, 0)
x
−2 −1
O
−1
1 2
−2
4 (0, 4)
3
2
1 (2, 0)
x
−2 −1
O
−1
1 2
−2
1
−1
−1
−2
−3
−4
O 1
(0, –1)
(1, −4)
x
d
y
e
y
f
y
(−2, 7)
7
6
5
4
3 (0, 3)
2
1
−3 −2 −1
O
−1
1 2
3
x
(−1, 3)
3
2
1
−2 −1
−1
−2
O
1
2
(0, −2)
x
(−6, 12)
−8 −6 −4
12
10
8
6
4
2
−2
O
−2
(0, 6)
2
x
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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