To write an expression in function notation, you must solve it for the dependent variable.
Assuming that you want the expression to be written in the form (i.e., assuming that x is the independent variable), we have to solve the expression for y, which means that we want y to remain alone on the left hand side, and move everything else to the right hand side.
So, first of all, we can add 9x to both sides to get
Finally, we divide both sides by 3:
rulers and compasses arent required in order to bisect an angle because when bisecting angles, you're making a "half circle" and considering in order to bisect an angle it wouldn't be straight, you wouldn't need either of the two