Answer:
(-4, -1)
Step-by-step explanation:
-3x - 8y = 20; y = 5x + 19
y = 5x + 19; -3x - 8y = 20
y = 5x + 19
-3x - 8y = 20
-3x - 8(5x + 19) = 20
-43x - 152 = 20
-43x - 152 + 152 = 20 + 152
-43x = 172
-43x / -43 = 172 / -43
x = -4
y = 5x + 19
y = (5)(-4) + 19
y = -1
I think it might be pairs 2 & 3
29°
triangles can only have 180°
This is a right triangle, so one angle is 90°, leaving us with 90° left
90°-61°= 29°
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

.