What is 125x9 + 64y12 written as a sum of cubes?

(25x3)3 + (4y4)3
(5x3)3 + (16y4)3
(25x3)3 + (8y4)3
(5x3)3 + (4y4)3

Let w=23 . what is the value of w + 45 ?

Don't know how to find x given these segment lengths

Aboat has a speed of 9 mph in calm water. it takes the boat 4 hours to travel upstream but only 2 hours to travel the same distance downstream. which equation can be used to find c, the speed of the current? 2(9 – c) = 4(9 + c) 9 + c = 4(9 – c) 9 – c = 2(9 + c) 4(9 – c) = 2(9 + c)