3x的6n次方+2x的4n次方乘x的5n次方
=3x^6n+2x^9n (1)
把x的3n次方=2代入(1)
=3(x^3n)^2+2(x^3n)^3
=3*2^2+2*2^3
=3*4+2*8
=12+16
=28
所以3x的6n次方+2x的4n次方乘x的5n次方的值是28
3x的6n次方+2x的4n次方乘x的5n次方
=3x^6n+2x^9n (1)
把x的3n次方=2代入(1)
=3(x^3n)^2+2(x^3n)^3
=3*2^2+2*2^3
=3*4+2*8
=12+16
=28
所以3x的6n次方+2x的4n次方乘x的5n次方的值是28