Determine the value of r so that the line through (5, 2) and (7, r) has a slope of m= -1/2

Y = mx + b
slope(m) = -1/2
(5,2)...x = 5 and y = 2
sub and find b
2 = -1/2(5) + b
2 = -5/2 + b
2 + 5/2 = b
4/2 + 5/2 = b
9/2 = b

so ur equation for this line is : y = -1/2x + 9/2

y = -1/2x + 9/2(7,r)when x = 7
y = -1/2(7) + 9/2
y = -7/2 + 9/2
y = 2/2
y = 1

so ur missing variable is 1ur set of points would then be (7,1) <=