Answer:
y = 5
Step-by-step explanation:
The first term (a1) is 9, and the common difference (d) is 4. Then the general term is ...
an = a1 + (n-1)·d = 9 + 4(n -1) = 4n +5
The "y-intercept" corresponds to the value when n=0. That value is ...
a0 = 4·0 +5 = 5
The y-intercept is 5.
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Comment on the problem
We have computed f(n) for n=0, but we must realize that n=0 is outside the domain of the function. This function only makes sense for integer values of n that are greater than zero. The "real" answer is that the y-intercept is "undefined."
