Answer:
The common difference (or common ratio) = 0.75
Step-by-step explanation:
i) let the first term be 
= 80
ii) let the second term be 
= . r = 80 × r = 60 ∴ r = 
= 0.75
iii) let the third term be 
= . r = 60 × r = 45 ∴ r = 
= 0.75
iv) let the fourth term be 
= . r = 45 × r = 33.75 ∴ r = 
= 0.75
Therefore we can see that the series of numbers are part of a geometric progression and the first term is 80 and the common ratio = 0.75.
Factor out the 4 in both equations
8a^2-20^2=(2^2 times a^2 times 2)-(2^2 times 5)
therefor it is also equal to
(2a)^2 times 2-(2^2 times 5)
we can force it into a difference of 2 perfect squares which is a^2-b^2=(a-b)(a+b)
(2a√2)^2-(2√5)^2=((2a√2)-(2√5))((2a√2)+(2√5))
Ask your teachers if you can still turn them in
It is the same. Even though you put a 0 in the end can't change the number
