X-1/2X+1-1×{[X-(X-1/2X+1)]×1/3}=14 X=?
问题描述:
X-1/2X+1-1×{[X-(X-1/2X+1)]×1/3}=14 X=?
答
X-1/2X+1-1×{[X-(X-1/2X+1)]×1/3}=14 X-1-{[X(2X+1)-(X-1)]×1/3}=14(2X+1) X-1-{[2X^2+X-X+1]×1/3}=28X+143X-3-2X^2-1=84X+422X^2+81X+46=0用公式法解得X=(-81+√81^2-4*2*46)/4=(-81+√6193)/4或X=(-81-√81^2-...