Slope and y-intercepts Quick Check

4 of 54 of 5 Items

Question
Use the image to answer the question.
An illustration of a coordinate plane with four quadrants shows the x and y axes extending from negative 5 to 5 in increments of 1. An upward slanting line is plotted on the coordinate plane. The upward slanting line with arrows at both ends passes through the following closed points: left parenthesis negative 4 comma start fraction negative 10 over 3 end fraction right parenthesis, and left parenthesis negative 1 comma start fraction negative 4 over 3 end fraction right parenthesis.

Determine the initial value and the rate of change of the linear function as given in the graph.

(1 point)
Responses

The initial value is −23
, and the rate of change is 23
.
The initial value is negative Start Fraction 2 over 3 End Fraction , and the rate of change is Start Fraction 2 over 3 End Fraction .

The initial value is 16
, and the rate of change is 32
.
The initial value is Start Fraction 1 over 6 End Fraction , and the rate of change is Start Fraction 3 over 2 End Fraction .

The initial value is 23
, and the rate of change is −23
.
The initial value is Start Fraction 2 over 3 End Fraction , and the rate of change is negative Start Fraction 2 over 3 End Fraction .

The initial value is −2
, and the rate of change is 23
.

1 answer

To determine the initial value (y-intercept) and the rate of change (slope) of the linear function represented by the line in the image, we can follow these steps:

  1. Finding the Slope (Rate of Change): The slope \( m \) can be calculated using the formula: \[ m = \frac{y_2 - y_1}{x_2 - x_1} \] Using the points provided: \[ (x_1, y_1) = (-4, -\frac{10}{3}) \quad \text{and} \quad (x_2, y_2) = (-1, -\frac{4}{3}) \] Substitute the coordinates into the slope formula: \[ m = \frac{-\frac{4}{3} - (-\frac{10}{3})}{-1 - (-4)} = \frac{-\frac{4}{3} + \frac{10}{3}}{-1 + 4} = \frac{\frac{6}{3}}{3} = \frac{2}{3} \]

  2. Finding the Initial Value (Y-intercept): The y-intercept occurs when \( x = 0 \). We can use the point-slope form of the equation of a line: \[ y - y_1 = m(x - x_1) \] Using one of the points \((-4, -\frac{10}{3})\): \[ y - (-\frac{10}{3}) = \frac{2}{3}(x + 4) \] Simplifying this, we can find the equation of the line. To find the y-intercept (when \( x = 0 \)): \[ y + \frac{10}{3} = \frac{2}{3}(0 + 4) \] \[ y + \frac{10}{3} = \frac{8}{3} \] \[ y = \frac{8}{3} - \frac{10}{3} = -\frac{2}{3} \]

So, the initial value (y-intercept) is \( -\frac{2}{3} \), and the rate of change (slope) is \( \frac{2}{3} \).

Final Answer: The correct option is: The initial value is negative Start Fraction 2 over 3 End Fraction, and the rate of change is Start Fraction 2 over 3 End Fraction.