for 7 all you need to do is subtract x from both sides to get y= 12- x, and to make it perpendicular you need to make the current slope it’s exact opposite so in this case that’s just changing the “-” symbol to an “+”.
for 8 you do the same first step you did in 7 and subtract 4x from both sides to get -y= 1 - 4x. Next you divide everything by -1 (because it’s the number in front of the Y) and you get Y= -1 + 4x
