Linear functions: How do you find slope from a table? and an example

11 answers

To find the slope from a table of values representing a linear function, you can look at the change in the y-values (vertical change) divided by the corresponding change in the x-values (horizontal change).

Here's an example to illustrate this process:

Suppose you have the following table for a linear function:

| x | y |
|----|----|
| 1 | 3 |
| 2 | 6 |
| 3 | 9 |
| 4 | 12 |

To find the slope, you need to choose any two points from the table. Let's select the points (1, 3) and (4, 12).

The change in the y-values is 12 - 3 = 9, and the change in the x-values is 4 - 1 = 3.

Therefore, the slope of the linear function is 9/3 = 3.

So, the slope of the linear function represented by this table is 3.
Linear functions: How do you know the y-intercept from a table? and an example
To determine the y-intercept from a table of values representing a linear function, you need to identify the point where the function intersects the y-axis, i.e., the point when x = 0.

Here's an example to understand this process:

Consider the following table for a linear function:

| x | y |
|----|----|
| 0 | 3 |
| 1 | 6 |
| 2 | 9 |
| 3 | 12 |

To find the y-intercept, you need to look for the point (0, y) in the table. In this case, (0, 3) is the point where the function intersects the y-axis.

Therefore, the y-intercept of the linear function represented by this table is 3.
Linear OR NonLinear Functions

How to tell from a table:

How to tell from a graph:

How to tell from an equation:
To determine whether a function is linear or nonlinear from a table, graph, or equation, you can use the following methods:

1. Table: Check if the differences between the corresponding y-values for each pair of x-values (the "y-differences" or "y-changes") are constant. If the y-differences are always the same, the function is linear. If the y-differences vary, the function is nonlinear.

2. Graph: Examine the shape of the graph. If the graph is a straight line, the function is linear. If the graph is curved or has any other shape, the function is nonlinear.

3. Equation: Look at the highest power (or degree) of the variable in the equation. If the variable has an exponent of 1, such as y = 2x + 3 or y = -5x, then the function is linear. If the variable has an exponent higher than 1 or appears in any other nonlinear form (e.g., y = x^2 or y = √x), then the function is nonlinear.

Example:

Table:
Consider the following table:

| x | y |
|----|----|
| 1 | 2 |
| 2 | 4 |
| 3 | 6 |
| 4 | 8 |

In this table, the y-differences are always 2 (e.g., 4-2=2, 6-4=2). Hence, the function is linear.

Graph:
If the graph of a function is a straight line, it is linear. For example, a graph of y = 3x + 2 would be a straight line, indicating a linear function.

Equation:
Examine the equation to determine if it is linear or nonlinear. For instance, the equation y = 5x^2 + 3 is nonlinear since the highest power of the variable x is 2.
Standard Form:

Point-Slope Form:

Slope-Intercept Form:
of Linear Equations
Standard Form:
The standard form of a linear equation is Ax + By = C, where A, B, and C are constants. In this form, both the x and y terms are on the same side of the equation, and the coefficients A, B, and C can be any real numbers.

Point-Slope Form:
The point-slope form of a linear equation is y - y1 = m(x - x1), where m is the slope of the line, and (x1, y1) is a point on the line. In this form, we have a specific point on the line and the slope of the line.

Slope-Intercept Form:
The slope-intercept form of a linear equation is y = mx + b, where m is the slope of the line, and b is the y-intercept (the value of y when x = 0). In this form, we can directly identify the slope and y-intercept of the line.
and an example
Sure! Here's an example of a linear equation in each form:

Standard Form: 2x + 3y = 6

Point-Slope Form: y - 4 = 2(x - 1)

Slope-Intercept Form: y = -3x + 2

These equations represent the same line, but they are written in different forms.
How do we change from one form to the other? and an example
To change a linear equation from one form to another, you can use algebraic manipulation and solve for the desired variables. Here's how you can convert between different forms:

1. Converting to Standard Form:
To convert an equation to standard form Ax + By = C, you need to ensure that A, B, and C are integers and that A is positive (if possible).
Example:
Convert the equation y = 2x + 3 to standard form.
Start by rearranging the equation: -2x + y = 3
Multiply the entire equation by -1 to make the coefficient of x positive: 2x - y = -3
The equation 2x - y = -3 is now in standard form.

2. Converting to Point-Slope Form:
To convert an equation to point-slope form y - y1 = m(x - x1), you need to know the slope (m) and a point (x1, y1) on the line.
Example:
Convert the equation y = 3x + 2 to point-slope form.
The slope is 3, and let's say we have a point (2, 8) on the line.
Substitute the values into the point-slope form: y - 8 = 3(x - 2)
The equation y - 8 = 3(x - 2) is now in point-slope form.

3. Converting to Slope-Intercept Form:
To convert an equation to slope-intercept form y = mx + b, you need to solve for y.
Example:
Convert the equation -2x + 3y = 6 to slope-intercept form.
Rearrange the equation to isolate y: 3y = 2x + 6
Divide both sides by 3: y = (2/3)x + 2
The equation y = (2/3)x + 2 is now in slope-intercept form.

Remember, the process of converting between forms necessitates algebraic manipulation, so ensure that you understand the properties and rules of algebra while making these conversions.