Posted by Chloe on .
Calculate the molar solubility of MgCO3 in a solution that already contains 1.7×10−3 M sodium carbonate.
MgCO3 Ksp = 6.82 x 106
IMPORTANT NOTE: You must use the quadratic equation to solve this problem.
(DrBob222 thank you so much for all your help!)

Chemistry 
DrBob222,
.........MgCO3 ==>Mg^2+ + CO3^2
I........solid....0.......0.0017
C.......for x.....x.........x
E.......solid.....x.........x+0.0017
6.82E6 = (x)(0.0017+x)
Solve for x = solubility in mols/L.