Answer:
D = -6, E = -8 , F = 0
Step-by-step explanation:
standard form = 
now, when circle passes through (3,-1);
⇒ 
⇒ 
...............( equation 1)
when circle passes through (-2,4);
⇒ 
⇒ 
...............( equation 2)
when circle passes through (6,8);
⇒ 
⇒ 
................( equation 3)
by solving these 3 equations , we get;
D = -6, E = -8, F = 0
hence,
standard form =
= 
First, recall that the equation of a line is
y = mx+b
where
m = slope
b = y-int
The key to this question is the details :
Horizontal line ---> This tells you that your slope is 0
y-int = 3.5 -----> In the equation above, b=3.5
Therefore,
y = 0x + 3.5
y = 0 + 3.5
y = 3.5
The original number to the nearest tenth is 23.8
