-66 is the 27th term.
You have a function in terms of n. Recall that n is the nth term in the sequence.
Substitute n = 27 into the equation to find the 27th term.
a₂₇ = -10 + (27 + 1)(-2) = -10 + (28)(-2) = -10 - 56 = -66
72 is multiples of 3,9, and 12
Answer:


can be a perfect square if the factor
is a paired.
Hence,
,will be a perfect square.

Hence,the square root is 

C. 2 is the difference of the values of the two variables in the system of equations hope this helps!