Answer: is a indeterminate number there is no number multiplied by zero that gives -6
Step-by-step explanation:
I can't read that language but I'll guess it says write a second degree equation then solve for n when d=10.



Answer: n² - 3n - 20 = 0
That doesn't factor so there is no integer n solution.
That means there are no polygons with 10 diagonals.

Answer:
r = -5
Step-by-step explanation:
common ratio (r) is found be dividing one term by its preceding term:
r = 275 ÷ -55 = -5
or, r = -55 ÷ 11 = -5
Therefore, r = -5