(1/4)^-2 (6x/7)^-2 simplify
(1/4)-2 = (4-1)-2 = 42 = 16
(6x/7)-2 = 6-2 · x-2 / 7-2 = 72 / ( 62 · x2 = 49 / (36x2)
16 · 49 / (36x2) = 784 / (36x2) = 196 / (9x2)