What is the value of the expression 7^–3?

Using the quadratic formula find the zeros of the given polynomial -5x^2+3x-11

What could explain what happened when the time was equal to 120 minutes

The ksp expression for the system pbcl2(s) pb+2(aq) + 2 cl-(aq) is: [pbc12][pb+2][2cl-] [pb+2][cl-]2 [pb+2][2cl-]2 [pbcl2][pb+2][cl-]2 [pb+2][2cl-]2[pbcl2]