If [tex]\( y = x + 5 \)[/tex] were changed to [tex]\( y = x + 9 \)[/tex], how would the graph of the new function compare with the first one?

A. It would be steeper.
B. It would be shifted right.
C. It would be shifted down.
D. It would be shifted up.



Answer :

Let's analyze this step by step:

1. Understanding the Original Function:
The original function given is [tex]\( y = x + 5 \)[/tex]. This is a linear equation in slope-intercept form [tex]\( y = mx + b \)[/tex], where [tex]\( m \)[/tex] is the slope and [tex]\( b \)[/tex] is the y-intercept.
- For [tex]\( y = x + 5 \)[/tex], the slope [tex]\( m \)[/tex] is 1, and the y-intercept [tex]\( b \)[/tex] is 5.

2. Understanding the New Function:
The new function given is [tex]\( y = x + 9 \)[/tex]. This is also in slope-intercept form.
- For [tex]\( y = x + 9 \)[/tex], the slope [tex]\( m \)[/tex] is still 1, but the y-intercept [tex]\( b \)[/tex] is now 9.

3. Comparing the Slopes:
Since both functions have a slope of 1, the steepness of their graphs is identical. This means Answer A is incorrect.

4. Finding the Vertical Shift:
Notice that the y-intercept of the first function is 5, and the y-intercept of the second function is 9. The difference between the y-intercepts is [tex]\( 9 - 5 = 4 \)[/tex].

5. Nature of the Shift:
Since the y-intercept has increased from 5 to 9, it indicates that the entire graph of the function [tex]\( y = x + 5 \)[/tex] has been moved vertically upwards by 4 units to obtain the new graph [tex]\( y = x + 9 \)[/tex].

6. Conclusion:
Therefore, the transformation from [tex]\( y = x + 5 \)[/tex] to [tex]\( y = x + 9 \)[/tex] is a vertical shift upwards by 4 units.

Thus, the correct answer is:

D. It would be shifted up.