MathAlgebra

Slope-Intercept Form of a Line: Edgenuity Answer

In slope-intercept form, moving a line vertically changes the intercept b without changing the slope m. For h(x) = -(2/3)x + 5, moving the graph down 3 units changes b from 5 to 2.

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 bb to 22.

The function is already in slope-intercept form:

h(x)=mx+b=23x+5h(x)=mx+b=-\frac{2}{3}x+5

Here, m=23m=-\frac{2}{3} controls the line's slope and b=5b=5 is the yy-intercept. Moving the entire graph down 3 units subtracts 3 from every output:

h(x)3=23x+53=23x+2h(x)-3=-\frac{2}{3}x+5-3=-\frac{2}{3}x+2

So the transformed line is

hnew(x)=23x+2.h_{new}(x)=-\frac{2}{3}x+2.

The slope remains 23-\frac{2}{3}, which means the new line is parallel to the original. Only its yy-intercept changes, from (0,5)(0,5) to (0,2)(0,2).

Why the other choices are incorrect

  • Changing bb to 3-3 moves the intercept from 55 to 3-3, a downward shift of 8 units rather than 3.
  • Changing mm to 3-3 changes the steepness of the line instead of translating it vertically.
  • Changing mm to 22 changes both the steepness and direction of the line; it does not produce a 3-unit downward shift.

Quick rule

For any line y=mx+by=mx+b, a vertical shift by kk units produces y=mx+(b+k)y=mx+(b+k). Keep mm unchanged and add the shift to bb. For a downward shift of 3, k=3k=-3, so bnew=5+(3)=2b_{new}=5+(-3)=2.

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.

Slope-Intercept Form of a Line Edgenuity Answers | Verla