D
Divide the whole thing by 2
2(X^2+8x-5)
X^2+8x. =5
Half of 8 is 4 sq it so you add 16
X^2+8x+16= 5+16
(X+4)^2=21
-- If the 55° angle is one of the two equal angles, then
the third angle is 70° .
-- If the 55° angle is the third angle, then each of the two
equal angles is 62.5° .
-- For either of these cases, there are an infinite number
of possible sets of side-lengths.
The statement in the question does not hold water.
The answer to -7 +11 -6 + 8 =6
C. 452.16
use formula pir^2
12^2 = 144
144 x 3.14 = 452.16
I used pi as 3.14