Answer:
As the y-intercept increases, the graph of the line shifts up;
As the y-intercept decreases, the graph of the line shifts down
Explanation:
There are two ways to think about this problem. The first way would be the graphical approach:
- if we only change the y-intercept, this means we keep the same slope;
- y-axis is the vertical axis;
- if we change the point at which the line crosses the y-axis, we either shift it upward for a higher y-intercept or downward for a lower y-intercept.
Now, thinking algebraically, a line has the following equation in a general form:
The y-intercept is essentially obtained when x = 0, then:
y = b:
- if we increase b value, the y value increases, so the graph shifts upward;
- if we decrease b value, the y value decreases, so the graph shifts downward.