Question

化简求值:2x²(x²-x-1)-x(2x³-10x²-2x-3)其中x=-1/2

Answer 1

你好

2x²(x²-x-1)-x(2x³-10x²-2x-3)
=2x ⁴-2x³-2x²-2x ⁴+10x³+2x²+3x
=8x³+3x
=8*（-1/8）+（-3/2）
=-5/2

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Answer 2

2x²(x²-x-1)-x(2x³-10x²-2x-3)其中x=-1/2

=2x^4-2x^3-2x^2-2x^4+10x^3+2x^2+3x
=8x^3+3x
=8*(-1/2)^3+3*(-1/2)
=-1-3/2
=-5/2

Answer 3

∵x=-1/2
2x²(x²-x-1)-x(2x³-10x²-2x-3)
=2x⁴-2x³-2x²-2x⁴+10x³+2x²+3x
=8x³+3x
=8×(-1/2)³+3×(-1/2)
=8×(-1/8)-3/2
=-1-3/2
=-2.5
参考http://58.130.5.100/