The Linear Function y=mx+b

🏆Practice linear function y=mx+b

The linear function y=mx+by=mx+b actually represents a graph of a straight line that has a point of intersection with the vertical Y Y axis.

m m represents the slope.
When m m is positive, the slope is positive: the line goes upwards.
When m m is negative, the slope is negative: the line goes downwards.
When m=0 m = 0 , the slope is zero: the line is parallel to the X X axis.

b b represents the point where the line intersects the Y Y axis.
If b=0 b=0 , then the line will pass through the origin of the coordinates, that is, the point (0,0) \left(0,0\right)

A - The Linear Function y=mx+b

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Test yourself on linear function y=mx+b!

For the function in front of you, the slope is?

XY

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How do we know if a point lies on a function?

If we are given a point, we can place it into the equation of a line to see if the equation holds true.
If we are given just one part of the point: X X or Y Y , we will put the given value into the equation correctly and find the second part of the point.


How do we graph the function?

If we want a precise drawing, we'll build a table of values with 3 3 or fewer values.
We replace X X each time and obtain the value of Y Y .
We consider the slope of the function to be increasing, decreasing, or equal to 0 0 , and then we graph it.


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What do we do if the slope is undefined?

To calculate the slope, we can use a formula that finds it using two given points that the line passes through:

m=(Y2Y1)(X2X1) m=\frac{\left(Y2-Y1\right)}{(X2-X1)}


A Lesson on Linear Functions

We are given a linear function y=3x+4 y=3x+4 .

We are asked to interpret the values 3 3 and 4 4 and plot the graph of the function.

First, it appears that m=3 m=3 , meaning 3 3 represents the slope of the line (or function).

b=4 b=4 means that the line intersects the vertical axis (the y-axis) at 4 4 .

To plot the graph, all we need are 2 2 points.
We substitute values and obtain:

1.a - An exercise on the linear function

Now we will mark the two points on the coordinate system and connect them.
Looking at the graph, we can confirm that the plot intersects the y-axis at the value of 4 4 .


Examples and exercises with solutions for the linear function

Exercise #1

For the function in front of you, the slope is?

XY

Video Solution

Step-by-Step Solution

To solve this problem, we need to determine the slope of the line depicted on the graph.

First, understand that the slope of a line on a coordinate plane indicates how steep the line is and the direction it is heading. Specifically:

  • A positive slope means the line rises as it goes from left to right.
  • A negative slope means the line falls as it goes from left to right.

Let's examine the graph given:

  • We see that the line starts at a higher point on the left and descends to a lower point on the right side.
  • As we move from the left side of the graph towards the right, the line goes downwards.

This downward trajectory clearly indicates a negative slope because the line is declining as we move horizontally left to right.

Therefore, the slope of this function is Negative.

The correct answer is, therefore, Negative slope.

Answer

Negative slope

Exercise #2

For the function in front of you, the slope is?

XY

Video Solution

Step-by-Step Solution

To solve this problem, let's analyze the given graph of the function to determine the slope's sign.

The slope of a line on a graph indicates the line's direction. A line with a positive slope rises as it moves from left to right, indicating that for every step taken to the right (along the x-axis), we move upward. Conversely, a line with a negative slope falls as it moves from left to right, meaning each step to the right results in moving downward.

Examining the graph provided, the red line starts higher on the left and goes downward towards the right visually. This indicates that the line is rising as it goes from left to right, which confirms it has a positive slope.

Therefore, the solution to the problem, regarding the slope of the line, is that it is a Positive slope.

Answer

Positive slope

Exercise #3

For the function in front of you, the slope is?

XY

Video Solution

Step-by-Step Solution

To solve this problem, let's evaluate the graph of the line provided:

  • The line is visually represented as starting from the bottom left to the top right, moving upwards.
  • In a standard Cartesian graph, a line that ascends as it progresses from left to right implies a positive change in the y-coordinate as the x-coordinate increases.
  • This upward trajectory indicates that the slope, m m , is positive.

Thus, the slope of the function is positive.

Therefore, the answer is Positive slope.

Answer

Positive slope

Exercise #4

For the function in front of you, the slope is?

XY

Video Solution

Step-by-Step Solution

To determine the slope of the line, we'll examine the direction of the line segment on the graph:

  • The line depicted moves from the top left, passing through a point with higher y y -coordinate values, to the bottom right, ending at a point with lower y y -coordinate values.
  • This movement indicates that as x x increases (the direction to the right along the x x -axis), the y y -coordinate decreases.
  • When the y y -value reduces as the x x -value grows, the slope m m is negative.

Since the line descends from left to right, the slope of the line is negative.

Therefore, the slope of the function is a negative slope.

Answer

Negative slope

Exercise #5

For the function in front of you, the slope is?

XY

Video Solution

Step-by-Step Solution

To solve this problem, follow these steps:

  • Step 1: Observe the given graph and the plotted line.
  • Step 2: Determine the direction of the line as it moves from left to right across the graph.
  • Step 3: Understand that a line moving downwards from left to right represents a negative slope.

Now, let's work through these steps:

Step 1: The graph shows a straight line that starts higher on the left side and descends towards the right side.

Step 2: As the line moves from left to right, it descends. This is a key indicator of the slope type.

Step 3: A line that moves downward from the left side to the right side of the graph (decreasing in height as it proceeds to the right) is characteristic of a negative slope. Conversely, a positive slope would show a line ascending as it moves rightward.

Therefore, the solution to the problem is the line has a negative slope.

Answer

Negative slope

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