Point J located at (2, 7) is rotated 90 degrees counterclockwise about (-1, -3). What is the y-coordinate of J’? A. 9
B. 0
C. -11
D. -9

Given:

Coordinates of point J are J(2,7).

It is rotated 90 degrees counterclockwise about (-1, -3).

To find:

The y-coordinate of J’.

Solution:

If a figure rotated 90 degrees counterclockwise about a point (a,b), then

Point J is rotated 90 degrees counterclockwise about (-1, -3). So, a=-1 and b=-3.

Coordinates of point J are J(2,7).

Therefore, the y-coordinate of J' is 0. Hence, the correct option is B.

the simplified form is

step-by-step explanation:

we want to simplify the expression,

let us change the middle bar to a normal division sign to obtain,

we multiply the first fraction by the reciprocal of the second fraction to obtain,

we factor to obtain,

we cancel the common factors to get,

we simplify to get,

the correct answer is b

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."