The slope-intercept form of the equation of a line is
where is the slope of the line and is the -intercept.
To illustrate, consider the line shown below.
Looking at the line, we notice that:
The slope of the line is because a change of in the -direction results in a change of in the -direction.
The -intercept of the line, denoted , is because the line hits the -axis at the point
Note: The coordinates of the -intercept are always
Finally, if the slope (i.e., we have a horizontal line), the slope-intercept form must be which reduces to
What are the slope and -intercept of the line
The equation is in slope-intercept form where is the slope and is the -intercept.
For the equation we see that the slope is and the -intercept is
Determine the slope and $y$-intercept of the line $y=4x-3.$
|
a
|
|
|
b
|
|
|
c
|
|
|
d
|
|
|
e
|
What are the coordinates of the point where the line $y = -9x + 17$ intersects the $y$-axis?
|
a
|
$(0,-9)$ |
|
b
|
$(0,-17)$ |
|
c
|
$\left(0,-\dfrac{9}{17}\right)$ |
|
d
|
$(0,17)$ |
|
e
|
$\left(0,\dfrac{17}{9}\right)$ |
What are the slope and $y$-intercept of the line $y = 3?$
|
a
|
The slope is $0$ and the $y$-intercept is $3$ |
|
b
|
The slope is $-1$ and the $y$-intercept is $1$ |
|
c
|
The slope is $3$ and the $y$-intercept is $0$ |
|
d
|
The slope is $0$ and the $y$-intercept is $1$ |
|
e
|
The slope is $0$ and the $y$-intercept is $-3$ |
The line shown above passes through the points and
We will write the equation of the line in the slope-intercept form So, we need to work out the slope and the -intercept
From the graph, we see that the line intercepts the -axis at So, the -intercept is
We can calculate the slope of the line by choosing two points on the line and applying the slope formula. The line passes through the points and so we calculate its slope as follows:
Substituting the slope and the -intercept into the slope-intercept form we obtain the equation of the line:
Given that the slope of the line shown above is $2,$ what is the equation of the line?
|
a
|
$y+2x=0$ |
|
b
|
$y=2x-3$ |
|
c
|
$y=2x+3$ |
|
d
|
$y=2x+1$ |
|
e
|
$y=3x+2$ |
The line shown above passes through the points $(0,1)$ and $(1,3).$ What is the equation of the line?
|
a
|
$y=2x-1$ |
|
b
|
$y=2x+1$ |
|
c
|
$y=x+1$ |
|
d
|
$y=x-1$ |
|
e
|
$y=3x+1$ |
Consider the line shown above, which has a slope of $\dfrac23.$ The equation of the line is $y=$
|
a
|
|
|
b
|
|
|
c
|
|
|
d
|
|
|
e
|
Find the equation of the line shown below.
We will write the equation of the line in the slope-intercept form So, we need to work out the slope and the -intercept
From the graph, we see that the line intercepts the -axis at So, the -intercept is
We can calculate the slope of the line by choosing two points on the line and applying the slope formula. The line passes through the points and so we calculate its slope as follows:
Substituting the slope and the -intercept into the slope-intercept form we obtain the equation of the line:
Given that the slope of the line shown above is $-2,$ what is the equation of the line?
|
a
|
$y=-2x-2$ |
|
b
|
$y=-x-1$ |
|
c
|
$y=-2x-1$ |
|
d
|
$y=-2x+2$ |
|
e
|
$y=2x+2$ |
The line shown above passes through the points $(0,5)$ and $(5,0).$ What is the equation of the line?
|
a
|
$y=-5x+5$ |
|
b
|
$y=5x+5$ |
|
c
|
$y=-x - 5$ |
|
d
|
$y=-x+5$ |
|
e
|
$y=-5x-5$ |
Calculate the equation of the straight line that passes through the points and
We will write the equation of the line in the slope-intercept form So, we need to work out the slope and the -intercept
First, we calculate the slope using the given points:
The coordinates of the -intercept are always We know that the line passes through the point so the -intercept is
Substituting the slope and the -intercept into the slope-intercept formula we reach
Find the equation of the line that passes through the points $(0,10)$ and $(4,26).$
|
a
|
$y=4x+10$ |
|
b
|
$y=2x+10$ |
|
c
|
$y=3x+26$ |
|
d
|
$y=4x+26$ |
|
e
|
$y=3x+10$ |
Find the equation of the line that passes through the points $(8,7)$ and $(0,31).$
|
a
|
$y=-2x+7$ |
|
b
|
$y=3x+31$ |
|
c
|
$y=-2x+31$ |
|
d
|
$y=-3x+7$ |
|
e
|
$y=-3x+31$ |
Written in the form $y=mx+b,$ what is the equation of the line that passes through the points $(3,-10)$ and $(0,-4)?$
|
a
|
|
|
b
|
|
|
c
|
|
|
d
|
|
|
e
|