Transcript PPT Equation of a line

EQUATIONS OF
STRAIGHT LINES
AIM: UNDERSTAND THE
GRADIENT AND INTERCEPT OF
A STRAIGHT LINE AND
EQUATIONS OF THE FORM
y=mx + c
The gradient is 2
because the line
slopes upwards 2 for
every one square
across
12
11
10
9
8
7
6
The equation of the line is
y = 2x + 1
2 up
5
4
3
1 across
2
Intercept is 1
1
00
1
2
3
4
5
6
What is the gradient
now?
The gradient is still 2
12
11
10
9
8
7
6
The equation of the line is
y = 2x + 1
4 up
5
4
3
2
Intercept is 1
2 across
1
00
1
2
3
4
5
6
The gradient is 4
because the line
slopes upwards 4 for
every one square
across
12
11
10
9
8
4 up
7
6
5
Intercept is 3
The equation of the line is
y = 4x + 3
1 across
4
3
2
1
00
1
2
3
4
5
6
The gradient is 3
because the line
slopes upwards 3 for
every one square
across
12
11
10
9
8
7
6
The equation of the line is
y = 3x + 2
Intercept is 2
3 up
5
4
3
1 across
2
1
00
1
2
3
4
5
6
The gradient is ½
because the line
slopes upwards ½ for
every one square
across
12
11
10
9
8
7
1 up
6
Intercept is 5
The equation of the line is
y=½x+5
5
2 across
4
3
2
1
00
1
2
3
4
5
6
The gradient is ⅔
because the line
slopes upwards ⅔ for
every one square
across
12
11
10
9
8
7
Intercept is 6
2 up
6
5
The equation of the line is
y=⅔x+6
3 across
4
3
2
1
00
1
2
3
4
5
6
12
11
Intercept is10
The gradient is -2
because the line
slopes downwards 2
for every one square
across
The equation of the line is
y = -2 x + 10
or
y= 10 – 2x
10
9
8
7
6
5
4
3
2 down
2
1
00
1 across
1
2
3
4
5
6
12
11
10
9
8
7
6
5
4
3
2
1
00
1
2
3
4
5
6
12
11
10
9
8
7
6
5
4
3
2
1
00
1
2
3
4
5
6
12
11
10
9
8
7
6
5
4
3
2
1
00
1
2
3
4
5
6