Mathematics Functions: Linear and Quadratic

Questions and Answers

What is the slope and y-intercept of the function represented by the equation $f(x) = -3x + 5$?

Slope: -5, Y-intercept: 3

Slope: -3, Y-intercept: 5 (correct)

Slope: 3, Y-intercept: -5

Slope: 5, Y-intercept: -3

Which of the following equations represents a quadratic function that opens downwards?

$f(x) = 3x^2 + 2x$

$f(x) = 2x^2 - 5x + 4$

$f(x) = 4x^2 - 2x + 1$

$f(x) = -x^2 + 3$ (correct)

Determine the vertex of the quadratic function $f(x) = 2x^2 + 4x + 1$.

Vertex: (1, 1)

Vertex: (-1, 3)

Vertex: (-1, -1) (correct)

Vertex: (1, 3)

What can be inferred about the graph of the linear function $f(x) = 0.5x + 3$?

The line crosses the y-axis at 3. Signup and view all the answers

In the quadratic function $f(x) = -3x^2 + 6x + 2$, what is the y-intercept?

2 Signup and view all the answers

For the quadratic function $f(x) = x^2 + 6x + 8$, what is the axis of symmetry?

$x = -3$ Signup and view all the answers

Which characteristic is true for the linear equation $f(x) = -5$?

The line is horizontal. Signup and view all the answers

Which of the following functions has a positive slope?

$f(x) = x - 3$ Signup and view all the answers

Study Notes

Mathematics Functions

Linear Functions

Definition: A function that graphs to a straight line.
Standard Form:
- ( f(x) = mx + b )
  - ( m ): slope (rate of change)
  - ( b ): y-intercept (where the line crosses the y-axis)
Characteristics:
- Slope indicates the direction of the line:
  - Positive slope: line rises from left to right.
  - Negative slope: line falls from left to right.
  - Zero slope: horizontal line (no change).
- Graph: Straight line; can be increasing or decreasing.
Examples:
- ( f(x) = 2x + 3 ) (slope = 2, y-intercept = 3)
- ( f(x) = -x + 1 ) (slope = -1, y-intercept = 1)

Quadratic Functions

Definition: A function that graphs to a parabola (U-shaped curve).
Standard Form:
- ( f(x) = ax^2 + bx + c )
  - ( a ): coefficient of ( x^2 ) (determines direction of the parabola)
  - ( b ): coefficient of ( x )
  - ( c ): constant term (y-intercept)
Characteristics:
- Opens upwards if ( a > 0 ) and downwards if ( a < 0 ).
- Vertex: The highest or lowest point of the parabola, calculated using ( x = -\frac{b}{2a} ).
- Axis of symmetry: Vertical line ( x = -\frac{b}{2a} ).
- Y-intercept: Found by evaluating ( f(0) = c ).
Examples:
- ( f(x) = x^2 - 4x + 3 ) (opens upwards, vertex at ( (2, -1) ))
- ( f(x) = -2x^2 + 4x - 1 ) (opens downwards, vertex at ( (1, 1) ))

Linear Functions

Definition: Represents a relationship where a variable changes at a constant rate, producing a straight line on a graph.
Standard Form:
- ( f(x) = mx + b )
  - ( m ): Represents the slope, indicating how steep the line is.
  - ( b ): The y-intercept, the point at which the line intersects the y-axis.
Slope Characteristics:
- Positive slope indicates the line ascends from left to right.
- Negative slope indicates the line descends from left to right.
- Zero slope indicates a horizontal line, signifying no change in the y-value with different x-values.
Graph Properties: Consists of straight lines that can be either increasing or decreasing based on the slope.
Examples:
- For ( f(x) = 2x + 3 ): slope is 2 (line rises) and y-intercept is 3 (crosses y-axis at (0,3)).
- For ( f(x) = -x + 1 ): slope is -1 (line falls) and y-intercept is 1 (crosses y-axis at (0,1)).

Quadratic Functions

Definition: Describe a parabolic relationship, yielding a U-shaped graph.
Standard Form:
- ( f(x) = ax^2 + bx + c )
 - ( a ): Determines whether the parabola opens upwards (if ( a > 0 )) or downwards (if ( a < 0 )).
 - ( b ): Influences the position of the vertex.
 - ( c ): The y-intercept, where the parabola crosses the y-axis.
Vertex: The highest or lowest point on the parabola, calculated using ( x = -\frac{b}{2a} ).
Axis of Symmetry: A vertical line represented by ( x = -\frac{b}{2a} ) that divides the parabola into two mirror-image halves.
Y-intercept: Detected by evaluating the function at zero, ( f(0) = c ).
Examples:
- For ( f(x) = x^2 - 4x + 3 ): opens upwards and has a vertex at ( (2, -1) ).
- For ( f(x) = -2x^2 + 4x - 1 ): opens downwards and has a vertex at ( (1, 1) ).

Description

This quiz covers key concepts and definitions of linear and quadratic functions. You will explore the standard forms, characteristics, and example equations of both function types. Test your knowledge on how to identify slopes and graph parabolas!