Question

已知：x^2 / (x^4+x^2+1)=1/4,计算(5x^4-3x^2+5) / 3x^2

Answer 1

x^2 / (x^4+x^2+1)=1/4

x^4+x^2+1=4x^2

x^4+1=3x^2

所以

(5x^4-3x^2+5) / 3x^2

=[5(x^4+1)-3x^2]/3x^2

=(5*3x^2-3x^2)/3x^2

=12x^2/3x^2

=4