So,
We know that we cannot add or subtract quantities of the same kind.
-18xy can only be added/subtracted to 4yx, which is the same as 4xy. The result would be -14xy, or -14yx.
The correct option is B.
Answer: 90 degrees clockwise
This is equivalent to 270 degrees counterclockwise
The rule for either rotation is 
The x and y coordinates swap places, and the new second coordinate flips from positive to negative (or vice versa).
The diagram below shows an example of this for the point (-4,-2) rotating to (-2, 4). The center of the rotation is the origin (0,0).
Answer:
i would say the 3rd one
Step-by-step explanation:
Given three points, it is possible to draw a circle that passes through all three. The perpendicular bisectors of a chords always passes through the center of the circle. By this method we find the center and can then draw the circle. This is virtually the same as constructing the circumcircle a triangle.
2/3, 4/5, 1/8 is the correct order from greatest to least.