Question

......

Answer 1

f(x) is same as y
so we can replace f(x) with y
\[\huge\rm \color{ReD}{y}=5\color{blue}{x}+12\]
to find inverse `switch x and y`
\[\huge\rm \color{blue}{x}=5\color{red}{y}+12\]
now solve for y

Answer 2

to solve for y first move 12 and and then 5 to the left side
\[\huge\rm \color{blue}{x}=5\color{red}{y}+12\]
how would you cancel out 12 from right side ?
would you add/subtract/multiply or divide ?

Answer 3

right so subtract 12 both sides :=))

Answer 4

no
both sides means
left and right hand side of the equal sign
you can't subtract 5 from 12
it's 5y