Question

二次根式竞赛题已知x=5-2√6,求3x^4-28x^3-17x^2+2x-10（凑0化简法）(过程!)注意：x是字母,

Answer 1

(5-x)^2=24,x^2-10x+25=24,x^2-10x=-1,

原等式=3x^2(x^2-10x)+2x^3-17x^2+2x-10

=2x^3-20x^2+2x-10

=2x(x^2-10x)+2x-10

=-10