①3x^2-11x-4=0(因式分解法) ②(x+2)(2x-1)=2(配方法) ③x^2+1/x+2x/x^2+1=3
问题描述:
①3x^2-11x-4=0(因式分解法) ②(x+2)(2x-1)=2(配方法) ③x^2+1/x+2x/x^2+1=3
答
3x^2-11x-4=0(3x+1)(x-4)=03x+1=0 x=-1/3x-4=0 x=4(x+2)(2x-1)=22x^2+3x-2=22(x^2+3x/2)=4(x^2+3x/2)=2(x+3/4)^2=2+(3/4)^2(x+3/4)^2=41/16x+3/4=±√41/16x=-3/4±√41/4x=(-3+√41)/4x=(-3-√41)/4(x^2+1)/x+2x/...