Answer:
9x^2 - 49y^2
Step-by-step explanation:
a 
7
because 4a + 7 - 7 35 - 7
equals 4a 28
and 4a/4 28/4
equals a 7
The rule of geometric sequence is ⇒⇒⇒ a * r^(n-1)
Where a is the first term and r is the common ratio
for the given sequence √5 , √10 , 2√5 , .......
a = √5
r = √10 / √5 = √2
The ninth term = √5 * (√2)^(9-1) = √5 * (√2)⁸ = 16 √5
the correct answer is the third option 16√5
1/7 is your answer. It can't be reduced any further. If there is supposed to be a problem, next time, add it.
