Your calculator cannot solve this problem for you. All you need is a knowledge of basic algebra and exponets:
6.3*10^-4 = 4x^3.
Divide both sides by 4:
x^3 = 1.575*10^-4
Take cube root of both sides:
(x^3)^(1/3) = (1.575*10^-4)^(1/3)
X = 1.1635*0.046416 = 0.05401.
Note: You can take the cube root of a
number by raising it to the 3rd power.