The mnemonic SOH CAH TOA helps you remember that
... Sin = Opposite/Hypotenuse
The side opposite angle K is marked with length 5. The hypotenuse KM is marked with length 10. Using the above relationship ...
... sin(∠K) = 5/10 = 1/2
The first choice is appropriate: 
Add v to both sides: -E=2+V
Divide both sides by -1: E= -2-V
Answer: -V-2
That is not correct, In a quotient or any type of equation numbers are considered rational number when they have repeating values, for this we will use {x} for example when comparing repeating values.
So if we have {a} + {b} from a equation prior to obtaining these values then we will take {a} + {b} and add {c} we will end up with {a} + {b} + {c}. We are using addition for an example.
{c} would only be a rational if it as well had repeating {x} values
{x}=Repeating value
