Given:
Consider the equation is

To find:
The value of x.
Solution:
We have,

Using properties of exponents, we get
![[\because \dfrac{a^m}{a^n}=a^{m-n},a^{-n}=\dfrac{1}{a^n}]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%5Cdfrac%7Ba%5Em%7D%7Ba%5En%7D%3Da%5E%7Bm-n%7D%2Ca%5E%7B-n%7D%3D%5Cdfrac%7B1%7D%7Ba%5En%7D%5D)
On comparing both sides, we get

Add 16 on both sides.


Multiply both sides by -1.

Therefore, the value of x is 8.
To find the number of years between 1844 to 2015 you have to subtract.
Lets say that x is the # of years in between 1844 and 2015
Then we have:

After doing the subtraction using a calculator or a pencil and paper, you get that:

So 171 years have passed from 1844 to reach to 2015.
Answer:
B. 77
Step-by-step explanation:
7 + x = 84
Subtract 7 from both sides
x = 77
Since these angles clearly form a circle and a circle is 360 degrees,
120-x+2x+16+3x-72=64+4x=360. Subtracting 64 from both sides, we get
4x=296 and by dividing both sides by 4 we get x=74
19.......................................