Probability??? Help please

What is the equation of the graph below? y=sec(x)-4

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]

Jenisey has $24 to spend on seven pencils. after buying them she had $10. how much did each pencil cost.?