Question

If `S=(n(a+1))/2` what is `n`?

Answer 1

`n=(2S)/(a+1)color(white)("XXX")`provided `(a+1)!=0`

Explanation:

Given
`color(white)("XXX")S=(n(a+1))/2color(white)("XX")`...at least that's how interpreted the question.

`(n(a+1))/2 = Scolor(white)("XXXX")`because we usually like to have the variable we are solving for on the left.

`rarr n(a+1) = 2Scolor(white)("XXXX")`after multiplying both sides by `2`

`rarr n= (2S)/(a+1)color(white)("XXXX")`after multiplying both sides by `(a+1)` and with the assumption that `a!=-1`#