1. ©G Dear 2010 – Not to be sold/Free to use
Applied Mathematic
(Preliminary Extension 1)
Straight
Line Graphs
Equation of a
Straight Line
Stage 6 - Year 11
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©G Dear 2010 – Not to be sold/Free to use

2. Equations of a Straight Line
General Form
ax + by + c = 0
m = - a b
Where and ‘c’ is the y-intercept.
End of
Slide

3. Equations of a Straight Line
Gradient Form
y = mx + b
Where
m is the gradient
and
b is the y-intercept.
End of
Slide

4. Equations of a Straight Line
Intercept Form
+ = 1 x a y b y
m = - a b
, b = b b - a b
 y =
+ b
[÷b] y b = - x a
[ ] + x a
+ 1 a x x a + y b
= 1
End of
Slide

5. Equations of a Straight Line Point-Gradient Formula
y – y1 = m(x – x1) y
y2 – y1
x2 – x1
m =
P(x,y)
y – y1
x – x1
 m =
A(x1,y1)
m(x – x1) = y – y1 x
End of
Slide

6. Equations of a Straight Line
Two-Point Formula
y – y1
x – x1
y2 – y1
x2 – x1 = y
P = (x,y),
∆APQ ||| ∆ABR
B(x2,y2)
P(x,y) PQ AQ BR AR
So =
A(x1,y1) Q R
y – y1
x – x1
y2 – y1
x2 – x1
i.e = x
End of
Slide