Question

Срочно помогите пж пж пж

Answer 1

Ответ:

$a=0,2(40)=0,240\, 40\, 40\, 40\, 40...\\\\10a=2,(40)\ \ ,\ \ \ \ 1000a=240,(40)\\\\1000a-10a=240,(40)-2,(40)\\\\990\, a=240-2\\\\990\, a=238\\\\a=\dfrac{238}{990}=\dfrac{119}{495}\\\\\\a^2=\Big(0,2(40)\Big)^2=\Big(\dfrac{119}{495}\Big)^2=\dfrac{14161}{245025}$