Answer:
Add the equations in order to solve for the first variable. Plug this value into the other equations in order to solve for the remaining variables.
X = 1
Y = 2
Im not sure about the given data but I plotted the scatter plot based on what I understand on how the data should be presented.
Time (years)
3, 6, 9, 12, 15, 18, 21, 24
Number of participants(x1000)
22, 25, 28, 14, 17, 20,15, 9
Attached is the scatter plot created online.
x = time (years)
y = number of participantep explanation
To find the midpoint of a line use the midpoint formula which is M = (x1+x2/2 , y1 +y2/2) After plugging in the coordinates for your variables you should get (-1+5/2, -1+2/2) This simplifies to (2, 1/2) which is the coordinates for the middle point of the base XY.
2y+14=28
-14=-14
—————-
2y=14
14/2=y
Y=7