Straight Lines

1
Straight Lines
x 5
y
y 1
y 3
x
x 3
2
Gradient or steepness
Sloping lines
y mx c
y - intercept or where the line cuts the
y - axis
3
Gradient (Slope)
Gradient change in y change
in x
2
Gradient 2 1 2
1
4
Find the gradient.
a
c
d
b
3/2
1
2
2/3
h
e
¾
½
-3
-2
g
f
i
j
-2/5
4
5
Find the gradient.
a
c
d
b
3/2
1
2
2/3
h
e
¾
½
-3
-2
g
f
i
j
-2/5
4
6
d
c
a
b
e
h
i
f
g
7
-1/4
d
c
a
b
-6/5
3
6/5
e
1/2
-3/2
h
i
-4
f
g
3/2
2/3
8
Remember there are two parts to the equation (or
name) of a line.
The gradient
2 1 2
2
The intercept
3
1
y 2x 3
9
What are the equations of these lines?
2.
1.
4.
3.
10
What are the equations of these lines?
2.
1.
y x - 2
y 2x 1
4.
3.
y ½x - 1
y 2 - x
11
(No Transcript)
12
y 1/3x 3
y 2x - 1
y x 4
y 3/2x 2
y ½x - 1
y 2x 4
13
y 5 - 5x
y 2x - 1
y ½x 5
y 5x - 1
y 2x 5
y 2x - 3
y 3 - 2x
y ½x - 1
14
y ½x - 1
y ½x 5
y 5x - 1
y 2x - 1
y 2x - 3
y 5 - 5x
y 2x 5
y 3 - 2x
15
Find the equation of the line that passes
through a) the blue points b) the red points
16
Find the equation of the line that passes
through a) the blue points b) the red points

• y 1/2x 2
• y 2x 1

17
What lines do I use to draw this square?
18
What lines do I use to draw this square?
y x 1
y -x - 1 or x y -1
y x - 1
y -x 1 or x y 1
19
Name those lines
20
These lines all go hrough the point (2 , 2) Can
you label them correctly?
Can you draw a similar diagram with 6 lines
going through the point (3, 3) or even (3,2)?