Answer:
Step-by-step explanation:
Arithmetic sequence:
In an arithmetic sequence, the difference between consecutive terms is always the same, and is called common difference.
The nth term is given by the following equation:
In which is the first term and d is the common difference.
First term is 9 common difference is -2
This means that
So, the nth term is given by:
Answer:
A and C
Step-by-step explanation:
solving the equations
A
x² - 4 = 0 ( add 4 to both sides )
x² = 4 ( take square root of both sides )
x = ± = ± 2 ← required solution
B
x² = - 4 ← has no real solutions
C
4x² = 16 ( divide both sides by 4 )
x² = 4 ( take square root of both sides )
x = ± = ± 2 ← required solution
D
2(x - 2)² = 0 , then
x- 2 = 0 ( add 2 to both sides )
x = 2 ← not the required solution