Answers:
bio = 258
sociology = 169
============================================================
Work Shown:
x = number of bio textbooks
y = number of sociology textbooks
x+y = 427 books sold total
y = x-89 since 89 less sociology textbooks were sold compared to bio
Apply substitution to get the following
x+y = 427
x+x-89 = 427 ... replace y with x-89
2x-89 = 427
2x = 427+89
2x = 516
x = 516/2
x = 258 bio textbooks were sold
y = x-89
y = 258-89
y = 169 sociology textbooks were sold
Answer:

Step-by-step explanation:
If AB is tangent to the circle, then angle ABO is right angle and triangle AOB is special
triangle. In this triangle, the leg that is opposite to the angle of 30° is half of the hypotenuse. Thus,

By the Pythagorean theorem,

The opposite of left is right, so the number opposite k is k units to the right.
Answer:
The vertical one is the y axis and the horizontal one is the x axis.
Step-by-step explanation:
For a better understanding of the solution provided here please find the diagram attached.
Please note that in coordinate geometry, the coordinates of the midpoint of a line segment is always the average of the coordinates of the endpoints of that line segment.
Thus, if, for example, the end coordinates of a line segment are
and
then the coordinates of the midpoint of this line segment will be the average of the coordinates of the two endpoints and thus, it will be:

Thus for our question the endpoints are
and
and hence the midpoint will be:


Thus, Option C is the correct option.