已知4X^2-2X-1=0,求(12X^5-6X^4-7X^3+2X^2+1)/(2X^3-X+1)的值
来源:学生作业帮 编辑:神马作文网作业帮 分类:数学作业 时间:2024/09/24 03:31:25
已知4X^2-2X-1=0,求(12X^5-6X^4-7X^3+2X^2+1)/(2X^3-X+1)的值
lijuan8687833 :
12x^5-6x^4-7x^3+2x^2+1
=4x^2(3x^3-x+1)-2x(3x^3-x+1)-(3x^3-x+1)-4x^2+2x+2
=(3x^3-x+1)(4x^2-2x-1)-(4x^2-2x-1)+1
=0-0+1
=1
2x^3-x+1
=1/2(4x^3-2x+2)
=1/2[x(4x^2-2x-1)+2x^2-x+2]
=1/2[x(4x^2-2x-1)+1/2(4x^2-2x-1)+5/2]
=1/2[(4x^2-2x-1)(x+1/2)+5/2]
=(1/2)×(5/2)
=5/4
∴(12x^5-6x^4-7x^3+2x^2+1)/(2x^3-x+1)
=1÷(5/4)
=4/5
12x^5-6x^4-7x^3+2x^2+1
=4x^2(3x^3-x+1)-2x(3x^3-x+1)-(3x^3-x+1)-4x^2+2x+2
=(3x^3-x+1)(4x^2-2x-1)-(4x^2-2x-1)+1
=0-0+1
=1
2x^3-x+1
=1/2(4x^3-2x+2)
=1/2[x(4x^2-2x-1)+2x^2-x+2]
=1/2[x(4x^2-2x-1)+1/2(4x^2-2x-1)+5/2]
=1/2[(4x^2-2x-1)(x+1/2)+5/2]
=(1/2)×(5/2)
=5/4
∴(12x^5-6x^4-7x^3+2x^2+1)/(2x^3-x+1)
=1÷(5/4)
=4/5
已知1+x+x^2+x^3=0,求x+x^2+x^3+x^4+x^5+x^6+x^7+x^8的值
已知1+x+x^2+x^3=0,求x+x^2+x^3+x^4+x^+x^6+x^7+x^8的值
已知 X=4- 根号3 求 (X*X*X*X-6X*X*X-2X*X+18X+23) / (X*X-8X+15)的值
已知x^4+x^3+x^3+x^2+x^1+1=0,求x^100+x^99+x^98+x^97+x^96的值
若x*x+x+1+0,求x^7+2x^6+x^5+x^4+x^3+x*x+1的值
已知x=2π+1求 |x-1|+|x-2|+|x-3|+|x-4|+|x-5|+|x-6|+|x-7|+|x-8|+|x
已知x^2+x+1=0,求1+x+x^2+x^3+x^4+.+x^2005的值.
已知x^3+x^2+x+1=0,求1++x+x^2+x^3+x^4+x^5+...+x^2007的值
已知1+x+x∧2+x∧3=0,求x+x∧2+x∧3+x∧4+x∧5+x∧6+x∧7+x∧8的值.
已知1十x十x^2 十x^3=0,求x十x^2十x^3十x^4+x^5十x^6+x^7十x^8的值
已知实数x满足5x*x-3x-5=0,求代数式5x*x-2x-1/5x*x-2x-5的值.
已知实数x满足5x*x-3x-5=0,求代数式5x*x-2x-[1/5x*x-2x-5]的值.