Assuming the series is

The series will converge if

We have

So the series will certainly converge if

, but we also need to check the endpoints of the interval.
If

, then the series is a scaled harmonic series, which we know diverges.
On the other hand, if

, by the alternating series test we can show that the series converges, since

and is strictly decreasing.
So, the interval of convergence for the series is

.
Answer:
42.5 units²
Explenation:
The area of the square on the left is 5×5=25.
At the top you do 12-5=7 to find the length of the tringle.
Than it is 7×5=35 than this divided by two, so 17.5.
You add both areas 25+17.5=42.5
(3, -2)
Step-by-step explanation:
y = -2x + 4
-x + 3y = -9
-x + 3 (-2x + 4) = -9
-x + -6x + 12 = -9
-7x = - 9 – 12
-7x = - 21
X = 3
We substitute x with 3 to evaluate y;
-3 + 3y = -9
3y = -6
y = -2
Elimination Method;
y = -2x + 4
-x + 3y = -9
We arrange the equations for substitution;
2x + y = 4
-x + 3y = -9
We multiply the first equation with 3 so we can substract one variable to zero;
3 (2x + y = 4)
= 6x + 3y = 12
Then we subtract the two;
6x + 3y = 12
-x + 3y = -9
7x = 21
x = 3
We evaluate y by substitution x with 3 in one of the equation;
-x + 3y = -9
-3 + 3y = -9
3y = -6
y = -2
The final answer expressed as a coordinate point is;
(3, -2)