Question

x(x*x*x-4x*x-4x+15)+18=0 这个方程怎么解

Answer 1

x^4-4x^3-4x^2+15x+18=0

x^4-3x^3-x^3+3x^2-7x^2+21x-6x+18=0

(x-3)(x^3-x^2-7x-6)=0

x1=3

x2=3.49449283705542

x3=-1.24724641852771-0.40170103640146i

x4=-1.24724641852771+0.40170103640146i