Yb = 3.6 (slider from -20 to 20, step 0.1)
Xb = 8 (slider from -20 to 20, step 0.1)
A = Intersect(xAxis, yAxis)
B: (Xb, Yb)
M_A = 17 (slider from 0 to 20, step 1)
M_B = 2 (slider from 0 to 20, step 1)
Xc = 9.360000000000003 (slider from -15 to 15, step 0.1)
Yc = -10.60000000000001 (slider from -15 to 15, step 0.1)
M_C = 4 (slider from 0 to 20, step 1)
C: (Xc, Yc)
D: (M_A * A + M_B * B + M_C * C) / (M_A + M_B + M_C)