Answer:

Step-by-step explanation:
Given the geometric sequence:
5, −10, 20, −40, ...
The first term is a = 5
And the common ratio = r = -10/5 = -2
The general rule of geometric sequence is

So, the rule for the given geometric sequence is:

Answer:
A
Step-by-step explanation:
Given 2 secants from a point outside the circle.
Then the product of the external part and the entire secant of one secant is equal to the product of the external part and the entire secant of the other secant, that is
(x + 1)(x + 1 + 11) = (x + 4)(x + 4 + 1)
(x + 1)(x + 12) = (x + 4)(x + 5) ← expand both sides
x² + 13x + 12 = x² + 9x + 20 ← subtract x² + 9x from both sides
4x + 12 = 20 ( subtract 12 from both sides )
4x = 8 ( divide both sides by 4 )
x = 2 → A