Central park is a rectangle with an area of 840 acres. it is 1/2 a mile wide. one acre is 43,560 square feet. two people start at the southwest corner at 1: 30 pm and start walking round the park in opposite directions. one walks at 9 mph, the other walks at 4 mph. how long until they meet again?

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