Use either:
balancePanel.Left = optionsPanel.Location.X;
or
balancePanel.Location = new Point(optionsPanel.Location.X, balancePanel.Location.Y);
See the documentation of Location:
Because the Point class is a value type (Structure in Visual Basic, struct in Visual C#), it is returned by value, meaning accessing the property returns a copy of the upper-left point of the control. So, adjusting the X or Y properties of the Point returned from this property will not affect the Left, Right, Top, or Bottom property values of the control. To adjust these properties set each property value individually, or set the Location property with a new Point.