The axis of symmetry is found within the set of parenthesis with the x. If our h value of the vertex is -4, then the axis of symmetry is x = -4. D is that choice. Cannot graph it here, but your vertex is sitting at (-4, 4), it's an upside down parabola, and some other points on this graph are (-5, 0), (-3, 0), (-6, -12), (-2, -12). You could graph it using those points and the vertex without a problem, I'm sure.
A geometric sequence is a sequence in which there is a common ratio between any two consecutive terms. In this case if X:Y:Z are in the ratio of 2:7:8 the multiplying by a constant k, we have X=2k, Y= 7k and Z=8k.
Then if X, Y-12, Z form a Geometric sequence, it means X/Y-12=Y-12/Z which is the same as 2k/7k-12=7k-12/8k if we cross multply, we get
16k²= 49k²-168k +144
33k²-168k+144 =0 solving for k
k = 4 or 1.091 if we take the whole number to find the values of X,Y and z,
X= 8, Y= 28 and Z=32
With the 3 colors - red=1, yellow=2 and green=5 - adding up to 8, that is one quarter the total of 32. Multiply each by 4 and you'll have - 4:8:20.
Using the law os cosines formula b^2 = a^2 + c^2 - 2*a*c*cos(B)
a = 17, b = 8, c = 16
8^2 = 17^2 + 16^2 - 2*17*16* cos(B)
64 = 289 + 256 - 544 * cos(B)
544*cos(B) = 289 + 256 - 64
544 * cos(B) = 481
cos (B) = 481/544
B = arccos(481/544)
B = 27.8 degrees
