Well to solve this problem, we must remember that Oxygen
in ionic form is Oxide O2- (an electric charge of negative 2). Hence the
correct formulas and names taking into account the charge of Oxygen are:
c) Co2O3, cobalt(III) oxide
f) CoO, cobalt(II) oxide
The correct option is
<span>D. Observation....</span>
The equation of 5m+4=7m+6 is equal to m=-1