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Stage 5.1-3

4.01 Gradient-intercept form

Worksheet
Gradient-intercept form
1

Consider the following three linear equations graphed on a number plane:

  • Equation 1: y = x + 1

  • Equation 2: y = 2 x + 1

  • Equation 3: y = 4 x + 1

a

What do all of the equations have in common?

b

What do all of the graphs have in common?

c

Describe all lines that have the form: y = m x + 1

-2
-1
1
2
x
-2
-1
1
2
y
2

Consider the following three linear equations graphed on a number plane:

  • Equation 1: y = 2 x + 4

  • Equation 2: y = 2 x + 8

  • Equation 3: y = 2 x - 4

a

What do all of the equations have in common?

b

What do all of the graphs have in common.

c

Describe all lines that have the form: y = 2 x + c

-8
-6
-4
-2
2
4
6
8
x
-8
-6
-4
-2
2
4
6
8
y
3

Determine whether or not the gradients of the following pairs of equations are equal:

a
i
y=7x
ii
y=7x-4
b
i
y=7x+2
ii
y=\dfrac{x}{7} +4
c
i
y=6-7x
ii
y=6x+7
d
i
y=4+7x
ii
y=7x-10
4

State the value of the y-intercept for following lines:

a

y = - 4 x + 1

b
y = 6 x - 2
c
y + 4 = -5 x
d

y = 2

e

5 x = 4 y

f

x = 1

g

y = 3 x

h
2 x + 6 y = 3
5

Consider the following linear equations:

i

State the value of the gradient, m.

ii

State the y-intercept, c.

a

y = - 2 x + 9

b

y = - 4 x - 8

c

y = 8 x + 6

d

y = - 1 - \dfrac{9 x}{2}

e
3y = 12x -15
f

- 9 x + 9 y = 27

g

3 x - 10 y =- 2

h
16x + 12y = 10
6

Find the equations of the following lines:

a

A line whose gradient is 2 and crosses the y-axis at 5.

b

A line whose gradient is - 6 and crosses the y-axis at 9.

c

A line whose gradient is - \dfrac{3}{4} and intercepts the y-axis at 3.

d

A line whose gradient is \dfrac{4}{3} and goes through the point \left(0, 3\right).

e

A line whose gradient is 8 and goes through the point \left(0, - 4 \right).

f

A line that has the same gradient as y = 9 - 8 x and the same y-intercept as

y = - 5 x - 3.

7

A line has a gradient of - 3 and intercepts the y-axis at - 2.

a

Write the equation of the line in the form y = m x + c.

b

State whether the point \left( - 2 , 4 \right) lies on this line.

8

A line has a gradient of - 3 and cuts the y-axis at 8.

a

Write the equation of the line in the form y = m x + c.

b

State whether the point \left( 8, - 31 \right) lies on this line.

9

Sketch the following lines on a number plane:

a

The line with a y-intercept of - 2 and gradient of - 3.

b

The line with a y-intercept of 3 and gradient of - \dfrac{3}{2}.

c

The line y = 2 x + 5.

d

The line y = \dfrac{1}{2} x - 1.

10

Consider the line graphed below:

a

State the the y-intercept.

b

State the gradient.

-4
-3
-2
-1
1
2
3
4
x
-4
-3
-2
-1
1
2
3
4
y
11

Consider the line graphed below:

a

State the y-intercept.

b

State the gradient.

-1
1
2
3
x
-2
-1
1
2
3
4
5
6
7
8
9
10
y
12

Consider the line graphed on the number plane:

a

State the values of:

i

The gradient, m.

ii

The y-intercept, c.

b

Write the equation of the line in gradient-intercept form.

c

Find the value of y when x = 27.

-2
-1
1
2
3
x
-2
-1
1
2
3
4
5
y
13

Consider the line graphed on the number plane:

a

State the values of:

i

The gradient, m.

ii

The y-intercept, c.

b

Write the equation of the line in gradient-intercept form.

c

Find the value of y when x = 28.

-2
-1
1
2
3
4
5
6
7
x
-6
-5
-4
-3
-2
-1
1
2
y
14
Consider the line graphed on the number plane:
a

State the value of the y-intercept.

b

By how much does the y-value increase as the x-value increases by 1?

c

Write the linear equation expressing the relationship between x and y.

-2
-1
1
2
x
-2
-1
1
2
y
15

Find the equations of the following lines in gradient-intercept form:

a
-1
1
2
3
x
-5
-4
-3
-2
-1
1
y
b
-2
2
4
6
8
10
12
14
16
18
x
-4
-3
-2
-1
1
y
c
-1
1
2
3
4
5
x
-3
-2
-1
1
y
d
-6
-5
-4
-3
-2
-1
1
x
-1
1
2
3
y
e
-2
-1
1
2
x
-2
-1
1
2
y
f
-1
1
2
3
x
-2
-1
1
2
3
4
5
6
y
g
-4
-3
-2
-1
1
2
3
4
x
-4
-3
-2
-1
1
2
3
4
y
h
-2
-1
1
2
x
-4
-3
-2
-1
1
2
y
16

For each pair of points:

a

Find the gradient of the line that passes through the points.

b

Find the equation of the line.

a

\left(0, - 10 \right) and \left( - 8 , - 26 \right)

b

\left(0, -1\right) and \left(7, 27\right)

17

For each of the following linear equations:

i

Rewrite it in the form y = m x + c.

ii

State the gradient of the line, m.

iii

State the y-intercept of the line, c.

a

y = \dfrac{- 4 x + 16}{4}

b

9 x - y - 8 = 0.

c

y = 3 \left( 4 x - 3\right)

d

y = 6 \left( 3 x - 2\right)

e

3 x - 9 y - 27 = 0.

f

3 x - 4 y - 28 = 0

18

Consider the line with equation y = \dfrac{8 - 5 x}{3}:

a

Express the line in the form y = m x + c.

b

Hence, what is the gradient, m, of the line?

19

Consider the lines with the following equations:

  • Line A: 5 x + 3 y + 5 = 0

  • Line B: 7 x + 6 y - 3 = 0

a

Express the lines in the form y = m x + c.

b

State which line is steeper, A or B.

General form of an equation
20

Express the following equations in general form.

a

y = 2 x - 3

b

y = \dfrac{2 x}{3} - 5

21

Consider the graph of the line:

a

What is the value of the y-intercept?

b

What is the gradient of the line?

c

Find the equation of the line in the form y = m x + c.

d

Express the equation of the line in general form ax + by + c = 0.

-4
-3
-2
-1
1
2
3
4
x
-7
-6
-5
-4
-3
-2
-1
1
2
3
4
y
22

A straight line intercepts the y-axis at 5 and passes through the point \left( - 5 , 10\right).

a

Find the gradient of the line.

b

Express the equation of the line in general form, ax + by + c = 0.

23

A straight line passes through the point \left(0 ,\dfrac{3}{4}\right) with gradient 4.

a

Find the equation of the line in the form y = m x + c.

b

Express this equation in the general form a x + b y + c = 0.

c

Find the x-intercept.

24

A line has a gradient of - 5 and passes through the point \left( - 2 , - \dfrac{3}{8} \right).

a

By substituting into the equation y = m x + c, find the value of c for this line.

b

Express the equation of the line in general form, ax + by + c = 0.

25

A line has a gradient of \dfrac{5}{4} and passes through the point \left( - 9 , - 9 \right).

a

By substituting into the equation y = m x + c, find the value of c for this line.

b

Express the equation of the line in general form, ax + by + c = 0.

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Outcomes

MA5.3-8NA

uses formulas to find midpoint, gradient and distance on the Cartesian plane, and applies standard forms of the equation of a straight line

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