Answer:

The world population at the beginning of 2019 will be of 7.45 billion people.
Step-by-step explanation:
The world population can be modeled by the following equation.

In which Q(t) is the population in t years after 1980, in billions, Q(0) is the initial population and r is the growth rate.
The world population at the beginning of 1980 was 4.5 billion. Assuming that the population continued to grow at the rate of approximately 1.3%/year.
This means that 
So


What will the world population be at the beginning of 2019 ?
2019 - 1980 = 39. So this is Q(39).


The world population at the beginning of 2019 will be of 7.45 billion people.
Answer:
WOMP WOMP WOMP!!!
Step-by-step explanation:
- Two angles that are complements of each other add to equal 90 degrees (they are complementary angles).
- One angle measures x degrees.
- The other angle measures 25 more than 4 times the angle that measures x degrees; it measures 4x + 25 degrees.
To find x, set the sum of these expressions (x and 4x + 25) equal to 90 and solve algebraically for x.
90 = x + (4x + 25)
90 = x + 4x + 25
90 = 5x + 25
65 = 5x
13 = x
If you wanted to find the measure of angle x, you'd substitute 13 for x in its expression, 4x + 25.
4x + 25
4(13) + 25
52 + 25
77
Answer:
x = 13
m∠x = 77°
You can solve the pair of equations graphically by finding where the two lines intersect/meet. The point where they intersect is the solution to both of the equations.
Slope-intercept form: y = mx + b
(m is the slope, b is the y-intercept, or the point where x = 0 ---> (0 , y))
y = 7x - 9
m = 7
y-intercept = -9 -----> (0, -9)
y = 3x - 1
m = 3
y-intercept = -1 ------> (0, -1)
I'm not really sure what the last sentence of the question is asking, so you could clarify the question if you need help