Question

Help me pleaseeeeeeeeeeeeeeeeeeeeee

Answer 1

A

Explanation:

`s=(a+b+c)/(2)`

multiply both sides by 2

`2s = a + b +c`

substract b and c from both sides to get a by itself

`a = 2s - (b + c)\\a = 2s - b - c`

so the answer is A.