Which reason justifies the last step in a proof that ∆def ≅ ∆dab?

given: line ad≅ line ed, d is the midpoint of line bf.

a. cpctc
b. asa postulate
c. sas postulate
d. aas theorem

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