Answer:

Step-by-step explanation:
This arithmetic sequence begins with 19, and for each consecutive value it subtracts 5. Therefore, the rule for this is:

Hope this helps!
Step-by-step explanation:
- First write the given equation

- Now take all polynomials to left side.


Answer:
After 15 years, the area will be of 775.3 km²
Step-by-step explanation:
The equation for the area of the forest after t years has the following format.

In which A(0) is the initial area and r is the yearly decrease rate.
A certain forest covers an area of 2600 km2.
This means that 
Suppose that each year this area decreases by 7.75%.
This means that 
So


What will the area be like after 15 years?
This is 


After 15 years, the area will be of 775.3 km²
Answer:
900cm^3
Step-by-step explanation:
1 cm= 10 mm
x=300mm (criss cross)
1cm*300mm/10mm= 10mm*x/10mm
30cm=x
30cm=300mm
1m=100cm
0.2m=x
1m*x/1m=0.2m*100cm/1m
x=0.2*100cm
x=20cm
0.2m=20cm
l=15cm
w=30cm
h=20cm
v=l*w*h
v=15cm*30cm*20cm
v=450cm^2*20cm
v=900cm^3
Answer:
Option 3.
Step-by-step explanation:
It is given that a triangle sits on a line and forms 2 exterior angles on the left and right of the triangle of (2h) degrees.
The top interior angle of the triangle is 40 degrees.

From the given figure it is clear that
(Supplementary angle)

(Supplementary angle)

According to the angle sum property of triangle, the sum of all interior angles of a triangle is 180 degree.
Combine like terms.
Divide both sides by -4.

The value of h is 55.
Therefore, the correct option is 3.