ANSWER
a=1
b=-12
Step-by-step explanation
The function has a hole at
x=3
The function also have a vertical asymptote at
x=-4.
This implies that, the denominator of the function is
![(x - 3)(x + 4)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9hcpccayvp2idt2wrh3df7fncfcls9gslw.png)
![{x}^(2) + 4x - 3x - 12](https://img.qammunity.org/2020/formulas/mathematics/middle-school/kl51o8nuxxd6z8d6eztj3d58vovfaeirdr.png)
![{x}^(2) + x - 12](https://img.qammunity.org/2020/formulas/mathematics/middle-school/cl47of7ll0kptf70kdxepm9ybhfmr1r1l7.png)
Comparing this to the function in the denominator,
![{x}^(2) + ax + b](https://img.qammunity.org/2020/formulas/mathematics/middle-school/18omgwg157rrm9tlqkvnlxp0nhawhdyt8j.png)
we have
a=1 and b=-12