Answer:
C. 
Step-by-step explanation:
y-2x-6 would be this expression factored
139 = x + (2x + 10)
139 = 3x + 10
129 = 3x
/3 /3
43 = x
Therefore
Beth would be four years old
Step-by-step explanation:
To multiply the fractions, like

Multiply the top,
then multiply the bottom.

Try to use a calculator if you aren't arithmetic heavy, but I suggest you to try to remember them because they are going to be helpful for courses like Algebra, Calculus, Statistics, etc.
To divide fractions, like

You take the top number,

Then you flip the bottom number,

Then multiply the two

And that is your answer. Comment if you need more clarification