Medical researchers have determined that for exercise to be beneficial, a person’s desirable heart rate, r, in beats per minute, can be approximated by the formulas
r=143-0.65a for women
r=165-0.75a for men,
where a represents the person’s age. if the desirable heart rate for a man is 135 beats per minute, how old is he?
a.22.5 years old
b.40 years old
c.45 years old
d.42.5 years old
evaluate the function
f(x)=1/2x+3
for f(4).
a. 5
b. 9
c. 11
d. 14

alright well the answers to your question is

2xy/9 hope this have a nice day : )

step-by-step explanation:

when rotating a figure 180 degrees, imagine that you are able to take the figure and turn it clockwise or counterclockwise around a center point. to rotate a figure 180 degrees, you will need to apply the rule (x, y) → (-x, -y). start by using a coordinate grid with coordinates for each vertex of the figure. the center point of the coordinate grid is located at (0, 0), which is what you will rotate the figure around. write down the original coordinates of the shape you are going to rotate. then, apply the rule. for example, coordinate (1, 2) becomes (-1, -2). another example would be, coordinate (-4, -2) becoming (4, 2). after you change each original coordinate to the rotated coordinate, you will draw your new figure.

step-by-step explanation: