Uh, if your asking to find m1 and m2, it would be impossible if neither are given, you would need at least one to solve for the other, if your asking to rearrange (which you probably are) the equation so u get m1 = something, and m2 = something, then it would be m1 = m2 (v2-u2)/(u1-v1) m2 = m1 (u1-v1)/(v2-u2)