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: C
Step-by-step explanation:
We know that
, and thus by the exterior angle theorem,

Thus, 
Henrietta solved a rational equation by multiplying both sides by
.She did not find the least common multiple of the denominators .If she had find the least common denominator which is 3x(x+2) then the question can have been simplified in more simpler form.
Henrietta can have got rid of denominator and then use the distributive rule .
So the first option
A:She could use the least common multiple of the denominator is right
X=-13/5
Simplify both sides of the equation, isolate the variable, and then you get your answer.