Gr10 writing linear equations

1. Writing Linear Equations
Using Slope Intercept Form

2. Slope-Intercept Form
•y = mx + b (c)
[or f(x) = mx + b]
•m is the slope/gradient
•b/c is the y-intercept

3. Find the Equation of the Line
•What is the
y-intercept?
•b = -2
•What is m?
•m =
•y = x -2
x
y
3
2
3
2

4. Find the Equation of the Line
•b = ?
•b = 1
•m = ?
•m =
-
•y =
-


x + 1
x
y
1
2
1
2

5. Find the Equation of the Line
•b = ?
•b = 4
•m = ?
•m = 0
•y = 0x+4
•y=4
x
y

6. Find the Slope and y-intercept of
each Equation:
1) y = -4x + 3
m = -4
b = 3
2) y = 5 - x
m =
-
b = 5
3) 8x + y =
m = -8
b =
4) 4x - 2y = 10
m = 2
b = -5
1
2
1
2
3
4
3
4

7. Find the Equation Given the
Slope and y-intercept
1) m = -3, b = 1
y = -3x + 1
2) m = - , b = -4
y = - x - 4
2
5
2
5

8. Find the Equation Given the
Slope and a Point
Given m = -1, (2, 1)
First, calculate b by substituting the slope and
the coordinates into y = mx + b.
y = -1x + b
1 = -1(2) + b
1 = -2 + b
3 = b
y = -1x + 3

9. Write the equation.
4gradient = 2, passes through (-4, 6)
4slope = -3/2, passes through (5, 3)

10. Find the Equation Given
Two Points
Given (-1, 3) and (2, 1)
First, calculate the slope:
Second, find b. Use either point...
m = , (2, 1)
1 = (2) + b
1 = + b

= b
( )
( )
m
- -
= =
--
1 3 2
2 1 3
-
2
3
-
2
3
-
4
3
7
3
y x=- +
2 7
3 3

11. Write the equation
4passes through (6, 1) and (8, -4)
4Passes through (-3, 5) and (2, 2)