It is known that any exponential function with the form f(x)=a^x is an increasing function while a function of the form g(x)=a^(-x) is a decreasing function.
Furthermore, it a function h(x) is increasing, then the function -h(x) is decreasing. By analogy, if a function k(x) is decreasing, then -k(x) is increasing.
Now let's analyze the functions from the problem.

Since (6/7)^x is increasing and the multiplying factor of 10 is positive, then the function <em>f(x)</em> is also increasing.
Use these rules to find whether each function is increasing or decreasing.
Remember that increasing functions are used to represent growth while decreasing functions are used to represent decay.
Answer:
8/40 = 20%
Step-by-step explanation:
Simply count the cubes in the blue rectangle, then count the cubes in the red rectangle. Divide red by blue, multiply that by 100. Thus giving your percent.
One way in which to approach this problem would be to treat it as an equation of ratios and to cross multiply:
<span>[(4x + 15) / 5x)] = 1/2 could be written as:
4x + 15 1
----------- = ---
5x 2
Then 8x + 30 = 5x
3x = -30, and so x = -10 (answer). Be certain to check this answer through substitution!
</span>
For this one your answer is -309