im guessing youre talking about number 4?
but you just gotta remember to keep doing the inverse of whatever type of multiplication until you get x or the variable by itself!
3x^2 - 12 = 0
add 12 to both sides to get
3x^2 = 12
then divide both sides to get
x^2 = 4
then take the square root of both sides to get your answer!
x = 2
