Center-of-mass of three balls

Three balls have masses and positions as follows:

The center-of-mass of this system is given by:
Xcom =
x1m1 + x2m2 + x3m3
m1 + m2 + m3
Xcom =
0.4 * 1.2 + (-0.4) * 2.1 + 0.1 * 1.7
1.2 + 2.1 + 1.7

Xcom = -0.038 m


Ycom =
y1m1 + y2m2 + y3m3
m1 + m2 + m3
Ycom =
0.7 * 1.2 + 0.7 * 2.1 + 0.2 * 1.7
1.2 + 2.1 + 1.7

Ycom = 0.53 m