chemistry
posted by roseanne .
Calculate the molar solubility of MX2, if the Ksp=3.3x10^8
i already asked this but im confused about one of the steps.
Ksp = (x)(2x)^2 = 4x^3 = 3.3X10^8
x = solubility = 0.00202M.
but i don't understand do i substitute the x in 4x^3 3.3X10^8 and then divide by 3.3X10^8. or am i wrong?

i tried solving it on my own but im confused by the steps and when i calculate i don't end up with 0.00202. please help!

4x^3 = 3.3E8
x^3 = (3.3E8/4) = 8.25E9
x= cube root(8.25E9) = 0.00202 M 
thanks! it looks like i was calculating the cube and not the cube root!