Given the polar point (8, -13/6) Find two other polar expressions for the point, one with a negative r value, and another with a positive r value....

Given the polar point (8, -13π/6)

Find two other polar expressions for the point, one with a negative r value, and another with a positive r value. Use exact values. 

Convert the polar point (8, -13π/6) into rectangular coordinates (x,y). Compute the coordinates exactly.