What two bits of information do you need to find the equation of a straight line ?

To find the equation of a straight line you need: the gradient of the line a point on the line (it could be the y-intercept)

Define the term y -intercept .

The y -intercept is where a graph crosses the y -axis .

If two lines are parallel then what is the relationship between the gradients of the lines?

If two lines are parallel then their gradients are equal .

GCSEMathsEdexcelFoundationFlashcardsAlgebraLinear Graphs

Linear Graphs (Edexcel GCSE Maths: Foundation): Flashcards

Exam code: 1MA1

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FrontEquations of Straight Lines (y = mx + c)
What does the constant $m$ represent in the equation of a straight line $y = m x + c$ ?
FrontEquations of Straight Lines (y = mx + c)
What two bits of information do you need to find the equation of a straight line?
BackEquations of Straight Lines (y = mx + c)
To find the equation of a straight line you need:
the gradient of the line
a point on the line (it could be the y-intercept)

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Cards in this collection (12)

What does the constant $m$ represent in the equation of a straight line $y = m x + c$ ?
In the equation of a straight line $y = m x + c$ , the constant $m$ represents the gradient of the line.
True or False?
In the equation of a line $y = m x + c$ , the constant $c$ tells you where the line crosses the x-axis.
False.
In the equation of a line $y = m x + c$ , the constant $c$ tells you where the line crosses the y-axis.
What two bits of information do you need to find the equation of a straight line?
To find the equation of a straight line you need:
- the gradient of the line
- a point on the line (it could be the y-intercept)
Define the term y-intercept.
The y-intercept is where a graph crosses the y-axis.
True or False?
The constant $c$ in the equation of a line $a x + b y + c = 0$ refers to the y-intercept.
False.
The constant $c$ in the equation of a line $a x + b y + c = 0$ does not refer to the y-intercept.
You need to rearrange it to make $y$ the subject.
How do you find the equation of a line if you know the gradient and a point on the line?
If you know the gradient of a line and a point on the line, then to find the equation:
- write $y = m x + c$ where $m$ is the gradient
- Substitute the coordinates of the point into the equation for $x$ and $y$
- Solve the equation to find $c$
How can you find the equation of a straight line if you have the coordinates of two points on the line?
If you have the coordinates of two points on a straight line then you can find the equation of the line $y = m x + c$ .
1. Find the gradient, $m$ , using the coordinates (e.g. form a right-angled triangle)
2. Substitute one pair of coordinates into $y = m x + c$ to find $c$
True or False?
The gradient of the line with the equation $2 x + y + 5 = 0$ is 2.
False.
The gradient of the line with the equation $2 x + y + 5 = 0$ is not 2. You need to write it in the form $y = m x + c$ first, giving $y = - 2 x - 5$ . Therefore the gradient is -2.
If two lines are parallel then what is the relationship between the gradients of the lines?
If two lines are parallel then their gradients are equal.
True or False?
The lines $y = 4 x + 5$ and $y = 3 x + 5$ are parallel.
False.
The lines $y = 4 x + 5$ and $y = 3 x + 5$ are not parallel because the gradients are different. They both have the same y-intercept.
How do you find the equation of a line if you know a point on the line and you know the equation of a line it is parallel to?
If you know a point on a line and you know the equation of a line it is parallel to then you can find the equation of the line:
- $m$ is equal to the gradient of the parallel line
- substitute the coordinates of the point into $y = m x + c$ and solve to find $c$
What is the gradient of a line that is parallel to the line $y = 3 x - 2$ ?
The gradient of a line that is parallel to the line $y = 3 x - 2$ is $3$ .

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