Đáp án:
↓↓↓
Giải thích các bước giải:
Theo đề, ta có:
$p$ $+$ $n$ $+$ $e$ $=$ $40$
$⇒$ $(1)$ $2p$ $+$ $n$ $=$ $40$
$(2)$ $2p$ $-$ $n$ $=$ $12$
Ta lấy $(1)$ $+$ $(2)$, suy ra:
$4p$ = $40$ $+$ $12$
$⇒$ $4p$ $=$ $52$
$⇒$ $p$ $=$ $52$ $÷$ $4$ $=$ $13$
$⇒$ $p$ $=$ $e$ $=$ $13$
Có: $2p$ $+$ $n$ $=$ $40$
$⇒$ $2$$.$$13$ $+$ $n$ $=$ $40$
$⇒$ $n$ $=$ $40$ $-$ $26$ $=$ $14$
$@Aqua$~$Shun$~