When the [h+] in a solution is 1.7 × 10−9 m, what is the poh

The pOH of a solution is related to the concentration of hydroxide ions in a solution. Also, it is related to the pH of the solution since the sum of pOH and pH is equal to 14. We can use this relation to solve this problem. We do as follows:

pH = -log[1.7 × 10−9 M] = 8.8
pOH + pH = 14
pOH + 8.8 = 14
pOH = 5.2

What? i don’t understand