Your parabola should look like this image. The vertex is at (-1, 9), and you can use any of the x-intercepts (-4, 0) & (2, 0) or the y-intercept (0, 8) as a second point.
The appropriate choice is ...
C. The slope of the first equation is not graphed the right way.A correct graph is shown below.
Since angle COB is the central angle of arc CB, the measure of arc CB = 80 degrees
The slope is m = 0 and the line goes through the point (x,y) = (2,3). So x = 2 pairs up with y = 3.
Plug m = 0, x = 2, y = 3 into the equation below. Then solve for b
y = mx+b
3 = 0*2+b
3 = 0+b
3 = b
b = 3
So if m = 0 and b = 3, then
y = mx+b
y = 0*x+3
y = 0+3
y = 3
is the equation of this line. This line is completely horizontal going through points like (0,3), (1,3), (2,3), etc. Every point on this line has a y coordinate of 3. The x coordinate can be any number you want.
Answer: Choice C) y = 3