Question

3.降次方法如果x平方-3x+1=0可以得知x平方=3x-z x立方=8x-4 x4次方=21x-8 x5次方=55x-

Answer 1

如果x平方-3x+1=0

x^2=3x-1

x^3=x*x^2

=x*(3x-1)

=3x^2-x

=3*(3x-1)-x

=9x-3-x

=8x-3

x^4=x^2*x^2

=(3x-1)*(3x-1)

=9x^2-6x+1

=9*(3x-1)-6x+1

=27x-9-6x+1

=21x-8

x^5=x^3*x^2

=(8x-3)(3x-1)

=24x^2-17x+3

=24(3x-1)-17x+3

=72x-24-17x+3

=55x-21