Question

помогите с алгеброй(7 класс)​

Answer 1

$\Big(\dfrac{1}{1999}-\dfrac{1}{2000}\Big)^2=\Big(\dfrac{2000-1999}{1999\cdot 2000}\Big)^2=\dfrac{1}{1999^2\, \cdot \, 2000^2}\\\\\\\Big(\dfrac{1}{2000}\Big)^2\cdot \Big(\dfrac{1}{1999}\Big)^2=\dfrac{1}{2000^2\, \cdot \, 1999^2}\\\\\\\\\dfrac{\Big(\dfrac{1}{1999}-\dfrac{1}{2000}\Big)^2}{\Big(\dfrac{1}{2000}\Big)^2\cdot \Big(\dfrac{1}{1999}\Big)^2}=\dfrac{2000^2\, \cdot \, 1999^2}{1999^2\, \cdot \, 2000^2} =1$