I reckon you'll be able to do this one if you put ur mind to it.
For this question, we need to find the force of attraction between the Earth and the Moon, and also the force of attraction between the Sun and the Moon. From there we can find the total force on the moon.
It will help a lot if you draw a quick diagram of the information you know for this one. You should basically have a triangle with the Sun, Moon and Earth at each corner.
We know the mass of each and the distance between the Eart and the Moon, so plug that info into the formula and get that force.
Remember the formula F = (M1*M2)/(R^2)?
We know the mass of the sun and the moon, but not the distance separating the, so let's find that first.
From your diagram, we can find a triangle with sides 385,108m and 1,501,011m. Using Pythagoras' Theorem we can find the hypotenuse.
Now we have the distance between the Sun and the Moon and the mass of each, so we can apply the formula to find the force of attraction.
Now we have 2 forces acting on the moon. By adding these vectors, we can find the total force acting on the moon.
Let me know if you're not familiar with vectors and I'll explain more.
Give it a shot and post your answer.