Wouldn't it be 2 since it goes into all them equally.
I'm not sure if A B C D are answers, but I can say for sure that C is positive and A, B, and D are negative.
A:

Since there is only one -1, the expression is negative;

B:

Here as well, there is only one -1, so the expression is negative;

C:

The -1 cancels out;

D:

Here, you can't cancel the -1 out, so it remains negative;

Sorry for the delay, hope this helps :)
Answer:
My example:
1. Get the equation in the form y = ax4 + bx + c
2. Calculate -b / 4a. This is the x coordinate of the vertex
3. To find the y coordinate of the vertex, simply plug the value -b / 4a into the equation for x and solve for y.
Step-by-step explanation:
y=2x^2 -16x +30
vertex: ( 4, -2)
Focus: (4, -15/8)
Axis of symmetry: x = 4
Directrix: y = -17/8
Answer:
3.5
Step-by-step explanation:
Changed them to decimals ( top number divided by the bottom will get you the decimal) and I got the answer. message me if you need more help