Help me please and thank you

Since the shape is a parallelogram, there are 2 pairs of opposite but equal sides --> "6a+21" and "20a+7"                   "11a" and "4a+7"

The easier pair is

11a = 4a+7              Subject 4a from both sides

7a = 7                     Divide 7 from both sides

a = 1

A = 1    

  2087568668/1  

step-by-step explanation:

a) 0.25x times 3. (could be wrong on equation.)

b) 2.25 pound of dark chocolate. (can i eat all the chocolate? plz? anyway, again, could be wrong, but i hope im right. all the chocolate together should be 5.25 pounds)

have a good day!