In complex calculations like this, the precedence goes like this
B = Brackets
O = Of (or Exponent)
D = Division
M = Multiplication
A = Addition
S = Substraction
So, in your formula, it will go like this
1/2x3+1/4x2
= 0.5 x 3 + 0.25 x 2
= 1.5 + 0.5
= 2
Hope this helps.
9 x 12 = 108
9 x 6 / 2 = 27
9 x 10 / 2 = 45
108 + 27 + 45 = 180
answer
area = 180 ft^2
The answers are
1. B
2. B
3. C
For a better understanding of the solution given here please go through the diagram in the file attached.
To solve this question we will make use of the "Triangle Angle Bisector Theorem", which states that, "An angle bisector of an angle of a triangle divides the opposite side in two segments that are proportional to the other two sides of the triangle."
Thus, in our question, we will have:

The above equation can be rearranged as:
...(Equation 1)
If we have a proper look at the denominator which is
, we note that in
, 
Thus, (Equation 1) wil give us:

<u>Therefore, LB= 12 feet</u>