Two points of the slope y=(2x+2) - 3 are (-1,0), (0,1)
Remark
I'm going to interpret this equation as
D = ut + kt² The only difference is the 2.
Solution
Subtract kt² from both sides.
D - kt² = ut Now divide by u on both sides.

The t's cancel out. on the right. You are left with u on the right.

Let,
the no. of adults be "x"
then, the no. of childern = total people - total adults
= (30 - x)
Now,
According to the quesiton,
2 (30 - x) + 5x = 87
60 - 2x + 5x = 87
60 + 3x = 87
3x = 87 - 60
3x = 27
x = 27 / 3
x = 9
So, there were 9 adults in the group
a) range of traditional= 84.6-56.1= 28.5
range of flipped is 91.5-63.8=27.7
the flipped course has more dispersion
c)range is now be : 601-56.1=544.9