PLEASE HELP ! The equation for the pH of a substance is pH = –log[H+], where H+ is the concentration of hydrogen ions. What is the approximate pH of a solution if the concentration of hydrogen ions is 5.0 × 10–4 moles per liter? Round to the nearest tenth if necessary

Eiko is wearing a magic ring that increases the power of her healing spell by 30%30\%30%30, percent. without the ring, her healing spell restores health points. which of the following expressions could represent how many health points the spell restores when eiko is wearing the magic ring?