Need help with math probelm if do 5 stars

Solve 2x+y=3 x+y=5 in substitution method

#1-20 state whether the angles are alternate interior, alternate exterior, vertical, or corresponding angles.

In the following diagram it is given that dec,ab || dc, ad || eb, and ad is congruent to bc. a)why isn't abc a parallelogram even though it has a pair of parallel sides and a pair of congruent sides b)explain why be must be congruent to bc. further explain what type of triangle this makes triangle abc and what it tells you about angle 1 and angle 2c) finally why must angle 3 be congruent to angle 1? further, explain why we know that angle 3 is congruent to angle 2