Which of the following choices is the common difference between the terms of this arithmetic sequence?

3x + 7y, 8x + 4y, 13x + y, 18x - 2y, 23x - 5y,

a. -5x - 3y
b. 3x + 7y
c. 5x - 3y
d. 5x + 3y
e. 3x - 7y

Abike shop sells you a bicycle for $63 and a helmet for $21. the total cost is 150% of what the shop spent originally. how much did the shop spend originally? how much profit did the bike shop earn by selling the bicycle and helmet to you ?

Need on this geometry question. explain how you did it.

In the diagram below,abc is congruent to dec what is the value of x