So the hypotenuse is the ladder's length, which is 6m, and the base of the 'triangle' is 1.5m. Therefore, you do 6^2 - 1.5^2 = 36 - 2.25 = 33.75. Then, you just square root it to get 5.80948m. Hope this helps!
Fifty decreased by twice a number is
2x-50
Just need to convert the mass of moon in terms of 10^24. So shift over 2 decimal places.
5.97 x 10^24 + 0.0734 x 10^24 = 6.04 x10^24