Theo đề ta có:
` p + n + e = 28`
`=> 2p + n = 28` ( Vì `p=e`) `(1)`
` 2p - n = 35, 715\% (2)`
Lấy `(1) + (2)` , ta có:
` 4p = 28 + 35, 715\%`
` 4p = 28 + 0,35715`
` 4p = 28, 35715`
`=> p = 28,35715 : 4`
`=> p = e = 7,0892875`
Ta có: `2p + n = 28`
hay : `2.7,0892875 + n = 28`
`=> 14,178575 + n = 28`
`=> n = 28 - 14,178575 = 13,821425`
$#Dyn.Shun$
$@Shun$~