Question 2 is one of balancing torque. Force (weight) on one side times its distance to the fulcrum must match the force (weight) on the other side times its distance to the fulcrum. Therefore, in the problem, we have 450N times 2 meters (half the seesaw) on one side. That equals 900 N-meters. On the other side we have 600 N times X meters for a total torque of 600N-meters. As an equation that would be:

(450 N) (2 meters) = (600 N) (X meters)

If we now divide both sides by 600 N, we would have:

1.5 meters = X where X is the distance sought.

Force x Distance to fulcrum x sin(angle force is applied to lever)

So neither is correct

2 using the formula above and assuming the angle the force is applied is at a right angle or 90 degrees leaves us with sin(90)=1 so that

450N times 2M = 600N times xM

solving for x leaves you with X = 900NM / 600N

X = 1.5 M