Can someone please HELP ME WITH THIS MATH PROBLEM FOR A P E X

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

Twelve less than a number is at most 20

Solve the equation: x - 9 = -6 + 5 a. 21 b. 7 c. 14 d. 2