Write the general formula first, then substitute the numbers.
It sounds like you're looking for help with a physics assignment based on the 8th-grade textbook by . Since you didn't specify a particular exercise or page number, I've outlined the core topics covered in this curriculum to help you identify what you need: Key Topics in Purysheva's 8th Grade Physics domashnee zadanie po fizike 8 klass purysheva
Electric current, voltage, resistance, Ohm’s law ( ), and series/parallel circuits. Write the general formula first, then substitute the numbers
Internal energy, heat transfer (conduction, convection, radiation), and calculating the amount of heat ( Write the general formula first
Reflection and refraction of light, and the basics of lenses. How to complete your "Paper" (Homework)