M(4, 2) is the midpoint of . the coordinates of s are (6, 1). what are the coordinates of r? (8, 0) (2, 3) (1.5, 3) (5, 1.5)

Assuming M is midpoint of RS

the midpoint formula is

x term of the midpoint is average of the x value of the 2 points
y term of the midpoint is average of the y value of the 2 points

if R is (x,y)

S is (6,1)

x value of midpoint is 4
x value of S is 6
x value os R is x

so
average of x and 6  is 4,
(x+6)/2=4,
x+6=8,
x=2

y value of midoint is 2
y value of S is 1
y value of R is y

average of 1 and y is 2
(y+1)/2=2
y+1=4
y=3

the midpoint is (2,3)