180 = C * A

180 = C * A

20 = C *A^3

Note that if we divide the first by A on both sides, we have  180 / A  = C ......and substituting this into the second thing, we have

20 = (180 / A ) A^3 

20 = (180) A ^2     divide both sides by 180

20/180 = 1/9 = A^2    taking the square root of both sides, we have

A = ±(1 / 3)

Therefore, C = 180 / ±(1 / 3) =  ±540

Thus, the solutions for (A, C) are (1/3 , 540) and (-1/3, -540)

Thanks!