(5x+2x²-3-4x³)-(-x+3x³-x²)其中x=2
(5x+2x²-3-4x³)-(-x+3x³-x²)
=5x+2x²-3-4x³+x-3x³+x²
=-7x³+3x²+6x-3
当x=2时,有:
-7x³+3x²+6x-3
=-7×2³+3×2²+6×2-3
=-56+12+12-3
=-35
(5x+2x²-3-4x³)-(-x+3x³-x²)其中x=2
(5x+2x²-3-4x³)-(-x+3x³-x²)
=5x+2x²-3-4x³+x-3x³+x²
=-7x³+3x²+6x-3
当x=2时,有:
-7x³+3x²+6x-3
=-7×2³+3×2²+6×2-3
=-56+12+12-3
=-35