Sorry this got to you super late. At least others looking for the answer can find it.
Answer with Step-by-step explanation:
Since we have given that
a + b = c
and a|c
i.e. a divides c.
We need to prove that a|b.
⇒ a = mb for some integer m
Since a|c,
So, mathematically, it is expressed as
c= ka
Now, we put the above value in a + b = c.
So, it becomes,

a=mb, here, m = k-1
Hence, proved.
When b=0
f(x)=ax^2+c
test each
A. with x^2-1, A is false
B. with -x^2-1, B is false
C. cannot find contradiction
D. the axis is actually x=0, 0 is nithere positive nor negative, false
answer is C
12^2=144
144 is divided by b which also is an odd interger, there only 2 numbers : 1 and 3
if b=3, a^2=48, then there will be no a available
if b=1 , a^2=144, then a is 12 and 12 can not be divided by 9
The answer is D