Evaluate 20-3x when x=2 and when x=3 which gives you the larger value

Given: △abc, ab=15, bd=9 ad ⊥ bc , m∠c=30°. find: the perimeter of the triangle.

What is the missing reason in the proof? segment addition congruent segments theorem transitive property of equality subtraction property of equality?

Solve: 25 points find the fifth term of an increasing geometric progression if the first term is equal to 7−3 √5 and each term (starting with the second) is equal to the difference of the term following it and the term preceding it.