6CO2 + 7H2O = C6H12O6 + 6O2 + H2O
Step-by-step explanation:
 CO2 + H2O = C6H12O6 + O2 + H2O 
 Starting carbon atoms, 
 1C on reactants and 6C on products, 
therefore you should start by putting a 6 on CO2 
 6CO2 + H2O = C6H12O6 + O2 + H2O 
 Proceed with Hydrogen, 
 Reactants → 2H 
 Products → 14H 
 You should multiply H2O with 7 . 
 6CO2 + 7H2O = C6H12O6 + O2 + H2O 
the we need to proceed for Oxygen, 
 Reactants → 12 + 7= 19O 
 Products → 6 O in C6H12O6, 2O in O2 and 1O in H2O 
 we need to balance the equation without disrupting the balance of other atoms, so we need to Multiply O2 with 6 
 The required balanced equation is 
6CO2 + 7H2O = C6H12O6 + 6O2 + H2O