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We have #color(red)((\root [ 11] { 9x ^ { 6} y } ) ^ { 7}#
Useful Exponent formula:
#color(blue)((a^m)^n = a^(mn)#
#color(blue)(root(n)m = m^(1/n)#
#color(blue)(root(n)(a^m) = a^(m/n)#
Consider:
#(\root [ 11] { 9x ^ { 6} y } ) ^ { 7}# given expression
Simplify this expression using the formula list above.
#[root(11)(9)*root(11)(x^6)*root(11)(y)]^7#
#rArr [root(11)(9^1)*root(11)(x^6)*root(11)(y^1)]^7#
#rArr [9^(1/11)*x^(6/11)*y^(1/11)]^7#
#rArr 9^(7/11)*x^(42/11)*y^(7/11)#
Hence,
#color(brown)((\root [ 11] { 9x ^ { 6} y } ) ^ { 7}= [9^(7/11)][x^(42/11)][y^(7/11)]#
Hope it helps.