Answer:

Step-by-step explanation:







A. population in 1975 ........................
Answer:
What is exactly the question?
Answer:
77.44%
49.87%
Step-by-step explanation:
If 12% leaks everyday, on the first day 12% would leak, leaving 100 - 125 = 88% of air
on the second day, 12% of 88% would leak = 0.88 x 0.12 = 0.1056
Air left on the second day = 88% - 10.56% = 77.44%
After a week = (100 - 12%)^7 = 49.87%
Simplifying
(0.75x + 6) + -1(2.5x + -1.9) = 0
Reorder the terms:
(6 + 0.75x) + -1(2.5x + -1.9) = 0
Remove parenthesis around (6 + 0.75x)
6 + 0.75x + -1(2.5x + -1.9) = 0
Reorder the terms:
6 + 0.75x + -1(-1.9 + 2.5x) = 0
6 + 0.75x + (-1.9 * -1 + 2.5x * -1) = 0
6 + 0.75x + (1.9 + -2.5x) = 0
Reorder the terms:
6 + 1.9 + 0.75x + -2.5x = 0
Combine like terms: 6 + 1.9 = 7.9
7.9 + 0.75x + -2.5x = 0
Combine like terms: 0.75x + -2.5x = -1.75x
7.9 + -1.75x = 0
Solving
7.9 + -1.75x = 0
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '-7.9' to each side of the equation.
7.9 + -7.9 + -1.75x = 0 + -7.9
Combine like terms: 7.9 + -7.9 = 0.0
0.0 + -1.75x = 0 + -7.9
-1.75x = 0 + -7.9
Combine like terms: 0 + -7.9 = -7.9
-1.75x = -7.9
Divide each side by '-1.75'.
x = 4.514285714
Simplifying
x = 4.514285714