Question

已知:x^2n=5,求（1/3x^3n)^2-3*(x^2)^2n的值

Answer 1

[(1/3)x^3n]^2-3(x^2)^2n

= (1/9)x^6n-3x^4n

= (1/9)(x^2n)^3-3(x^2n)^2

= (1/9)*5^3-3*5^2

= -550/9