Which is an arithmetic sequence?

a) 9,12,16,20
b)9,11,13,16
c)1,5,9,13,17
d)1/2,1/4,1/6,1/8

Astudent draws two parabolas on graph paper. both parabolas cross the x-axis at (-4, 0) and (6,0). the y-intercept of thefirst parabola is (0, –12). the y-intercept of the second parabola is (0-24). what is the positive difference between the avalues for the two functions that describe the parabolas? write your answer as a decimal rounded to the nearest tenth.