Answer:
∠ ABC = 81° , ∠ FEC = 90°
Step-by-step explanation:
Since AB ≅ BC then Δ ABC is isosceles.
The median BE is therefore
The angle bisector of ∠ ABC and
BE bisects AC at right angles.
Thus
∠ ABE = ∠ CBE = 40° 30' , then
∠ ABC = 2 × 40° 30' = 81°
Since BE is perpendicular to AC then
∠ FEC = 90°
A = 9y+3xy
take 3y as a common factor:
a = 3y(3+x)
this is the simplest form of this expression.