The first two are equivalent to 15 = k + 13
8 = k + 13 - 7 → ( add 7 to both sides )
8 + 7 = k + 13 ⇒ 15 = k + 13 ' is equivalent '
12 = k + 13 - 3 → ( add 3 to both sides )
12 + 3 = k + 13 ' is equivalent '
An inverse function reverses (x, f(x)) to make it (f(x), x).
The 1st selection does that.
I know these are all the factors of 12
1,2,3,4,6,12
Its is two since you take out the decimals then divide regularly
Using a Protractor..
It's a little plastic half circle thingy with angle measurements on it.
see image below