Answer:
B
Step-by-step explanation:
Law of Quadrilaterals.
I think this is correct, how it helps.

x equals 25% of the cost.
.25 equals 25%
Therefore x=12
The awnser is $12
Answer:
coefficent matrix
Step-by-step explanation:
P. 366
"If the column of constant terms is not included, the matrix reduces to that of the coefficent matrix of the system"
-1 -3 -1
9 -9 -1
-1 -3 4
If sinα=1/4 and it is in q2 it means that the x coordinate is negative.
The triangle has a height of one and a hypotenuse of 4 so:
x=-√(4^2-1)
x=-√15
so tanα=-1/√15
tanα=-√(1/15)
tanα≈ -0.258