check the picture below.
so the ellipse looks more or less like so, let's notice, the distance from the center of the ellipse to a foci is c = 2, and the "a" component or half the major axis is a = 4.
-4-8= -12
8-2=6
12+6=18
-12b+6c+18
Greatest common factor = 6
-12/6=-2
6/6=1
18/6=3
D 6(-2b+1c+3)
-12(2)+6(-3)+18
-24+(-18)+18
-42+18= -24
-24
Answer:
Step-by-step explanation:
, which is also equal to .
Proof method:
1. Calculate the length of each side, DE,DF,EF
2. Compare the length of them, if any pair of them is equal, then it's isosceles.
-7y+8=21x-6
-7y=21x-14
y=-3x+2
y=-3(0)+2=2 (0,2)
y=-3(1)+2=-1 (1,-1)
y=-3(2)+2=-4 (2,-4)