Math Released Item 2018 Grade 8 Slope Intercept Form VH049778
Anchor Set A1 A8 With Annotations
Prompt
Score Description VH049778 Rubric 3 Student response includes the following 3 elements. Computation component = 1 point o The student indicates a valid equation of the graphed line is y= 1 x + 4 or an equivalent equation where the slope 2 and the slope and y-intercept are immediately evident (for example y= 4 0.5x) Reasoning component = 2 points o Valid explanation of a method to find the slope of the graphed line o Valid explanation of a method to find the y-intercept of the graphed line Sample Student Response: I found two points on the line and subtracted the x- and y- coordinates and divided the change in the y-coordinates by the change in the x-coordinates OR other equivalent description. Since the graph appears to cross the y-axis at (0,4), the y- intercept of the line is 4. Notes: The point can be earned, even if the coordinates used for the calculation are not shown. The student does not have to use the terms intercept and slope to receive a point for reasoning. The student could also be given credit for both parts if they write the equation y=mx + b, select two points on the graph of the equation, and use the x and y values of the points to solve the system of equations for m and b. 2 Student response includes 2 of the 3 elements. 1 Student response includes 1 of the 3 elements. 0 Student response is incorrect or irrelevant.
A1 Score Point 3
Annotation Anchor Paper 1 Score Point 3 This response receives full credit. The response includes each of the three required elements. This response provides a valid equation of the graphed line (y = 1 2 x + 4). This response explains how to find the slope of the graphed line (I saw that the line went up one space and over -2 spaces and converted that into 1 2 ). This response explains how to find the y-intercept of the graphed line (I went to where the line croses the y axis at 4 and that is the y intercept).
A2 Score Point 3
Annotation Anchor Paper 2 Score Point 3 This response receives full credit. The response includes each of the three required elements. This response provides a valid equation of the graphed line (y = 0.5x + 4 ). This response explains how to find the slope of the graphed line (for every 1 on the x axis, the line goes down 1 2 ). This response explains how to find the y-intercept of the graphed line (the line is at the y axis at 4).
A3 Score Point 2
Annotation Anchor Paper 3 Score Point 2 This response receives partial credit. The response includes two of the three required elements. This response explains how to find the slope of the graphed line (To find the slope i looked and saw that it went down 1 and right two between points). This response explains how to find the y-intercept of the graphed line (To find the Y int I saw that it crossed the y axis at where Y=4). This response does not provide a valid equation of the graphed line.
A4 Score Point 2
Annotation Anchor Paper 4 Score Point 2 This response receives partial credit. The response includes two of the three required elements. This response explains how to find the slope of the graphed line (I found the slope by using the rise over run method. Up on over negative two). This response explains how to find the y-intercept of the graphed line [I found the y intercept by looking at where the line crosses the y axis (4)]. This response does not provide a valid equation of the graphed line. The equation provided is missing the variable x (y = 1 2 + 4 ).
A5 Score Point 1
Annotation Anchor Paper 5 Score Point 1 This response receives partial credit. The response includes one of the three required elements. This response explains how to find the y intercept of the graphed line (I figured out the answer by looking at the Y axis line and seeing that the line crosses it at 4). This response does not provide a valid equation of the graphed line ( 2 1 x + 4). This response does not explain how to find the slope of the graphed line.
A6 Score Point 1
Annotation Anchor Paper 6 Score Point 1 This response receives partial credit. The response includes one of the three required elements. This response provides a valid equation of the graphed line (y = 1 2 x + 4). This response does not explain how to find the slope of the graphed line. This response does not explain how to find the y-intercept of the graphed line.
A7 Score Point 0
Annotation Anchor Paper 7 Score Point 0 This response receives no credit. The response includes none of the three required elements. This response does not provide a valid equation of the graphed line. This response does not correctly explain how to find the slope of the graphed line [slope: it start at (-4,6) and the next point is (-2,5) so the slope is easy it s 2 over and 1 down]. This description provided is run over rise, not rise over run which is incorrect. This response does not explain how to find the y-intercept of the graphed line.
A8 Score Point 0
Annotation Anchor Paper 8 Score Point 0 This response receives no credit. The response includes none of the three required elements. This response does not provide a valid equation of the graphed line. This response contradicts itself by incorrectly identifying the slope as (0,4) [the slope of this line is (0,4) because thats where it crosses the y axis] instead of the y-intercept. This response does not explain how to find the y-intercept of the graphed line.
Practice Set P1 - P5 No Annotations Included
P1
P2
P3
P4
P5
Practice Set Paper Score P1 2 P2 3 P3 1 P4 3 P5 2