9th,10th,11th,12th, important formula's which is Very usefully Hi Friend's Today, we are telling you some math formula's which are important for children's and for Elders also many times When we do not have a book, but we need some formula's to solve some math problems then we check formula's in different places. But not all get the same place, so today we will try to do the same thing a little easier Third party image reference Some basic formula's which is everybody should know 1. (α+в)²= α²+2αв+в² 2. (α+в)²= (α-в)²+4αв 3. (α-в)²= α²-2αв+в² 4. (α-в)²= (α+в)²-4αв 5. α² + в²= (α+в)² - 2αв. 6. α² + в²= (α-в)² + 2αв. 7. α²-в² =(α + в)(α - в) 8. 2(α² + в²) = (α+ в)² + (α - в)² 9. 4αв = (α + в)² -(α-в)² 10. αв ={(α+в)/2}²-{(α-в)/2}² 11. (α + в + ¢)² = α² + в² + ¢² + 2(αв + в¢ + ¢α) 12. (α + в)³ = α³ + 3α²в + 3αв² + в³ 13. (α + в)³ = α³ + в³ + 3αв(α + в) 14. (α-в)³=α³-3α²в+3αв...