Solving+exponential+equationsSet+6

Solve For X

(x^4/5)+7(x^2/5)+6=0

(x^6/8)+18(x^3/8)+81=0 x6+18x3+81 (x3+9)(x3+9) -Avi Molder

(x1/5)4+(7x1/5)2+6 x1/5=x x4+7x2+6=0 (x2+6)(x2+1)