Choice A is one of the answers. Nice work. This is because x+x+x turns into 3x.
Choice D is the other answer because 2(x+1) + x = 2x+2+x = 3x+2. You can find this through trial and error. Or you could graph y = x+x+x+2 and y = 2(x+1)+2 to find that they are the same exact identical diagonal line. A non-graph approach would be to set up a table of values to see that the two tables are identical.
I believe it is 128. I may be wrong but if there are 384 tickets sold and there were 2 times more student tickets sold than adult then there are 128 tickets lift over to be adult tickets
volume of a sphere = 4/3 *pi * r^3
3/4 * pi = 4/3 *pi * r^3
divide each side by pi
3/4 = 4/3 * r^3
multiply each side by 3/4
3/4 * 3/4 = r^3
9/16 = r^3
take the cube root of each side
r = (9/16) ^ (1/3)