Ans(a):
Given function is
![f(x)=(3x-1)/(x+4)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/zow0hemr6a9odk0roozcj29ybcar0k6qmh.png)
we know that any rational function is not defined when denominator is 0 so that means denominator x+4 can't be 0
so let's solve
x+4≠0 for x
x≠0-4
x≠-4
Hence at x=4, function can't have solution.
Ans(b):
We know that vertical shift occurs when we add something on the right side of function so vertical shift by 4 units means add 4 to f(x)
so we get:
g(x)=f(x)+4
![g(x)=(3x-1)/(x+4)+4](https://img.qammunity.org/2019/formulas/mathematics/middle-school/n8wmu4a57wijninro6syn1hfenaao35itr.png)
We may simplify this equation but that is not compulsory.
Comparision:
Graph of g(x) will be just 4 unit upward than graph of f(x).
Ans(c):
To find value of x when g(x)=8, just plug g(x)=8 in previous equation
![8=(3x-1)/(x+4)+4](https://img.qammunity.org/2019/formulas/mathematics/middle-school/x04r2y3v1bhyg07v9l2gks9l88vcvr0hef.png)
![8-4=(3x-1)/(x+4)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/z0wsw224aw755pqw8bn5ch425o0lqqtfwo.png)
![4=(3x-1)/(x+4)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/yk662ls81ozn31i7c3mcb4y9rtzlmptj13.png)
![4(x+4)=(3x-1)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/p7u8us8m9gt654w4hlmc64ykqy3uix811c.png)
![4x+16=3x-1](https://img.qammunity.org/2019/formulas/mathematics/middle-school/j2ji74bkdpwo5msv2fngfeng7iehfzu8oq.png)
4x-3x=-1-16
x=-17
Hence final answer is x=-17