Question
Slope-Intercept Form of a Line — Try ItConsider the function h(x) = -(2/3)x + 5. Which value could you change to move the graph down 3 units?A. Change the value of b to -3.B. Change the value of m to -3.C. Change the value of b to 2.D. Change the value of m to 2.
Answer
Change the value of to .
The function is already in slope-intercept form:
Here, controls the line's slope and is the -intercept. Moving the entire graph down 3 units subtracts 3 from every output:
So the transformed line is
The slope remains , which means the new line is parallel to the original. Only its -intercept changes, from to .
Why the other choices are incorrect
- Changing to moves the intercept from to , a downward shift of 8 units rather than 3.
- Changing to changes the steepness of the line instead of translating it vertically.
- Changing to changes both the steepness and direction of the line; it does not produce a 3-unit downward shift.
Quick rule
For any line , a vertical shift by units produces . Keep unchanged and add the shift to . For a downward shift of 3, , so .
Evidence boundary
This answer addresses the publicly visible Edgenuity Try It item using h(x) = -(2/3)x + 5 and a downward shift of 3 units. Edgenuity course versions and randomized quiz items can use different equations or choices, so the result should not be transferred to a different prompt without checking its displayed values.
Sources
These references support the concepts and methods used in the explanation above.