第2个回答 2023-01-22
(x²+3x-2)(x²+5x+4)-16
=[x^2+4x+1-(x+3)][x^2+4x+1+(x+3)]-16
=(x^2+4x+1)^2-(x+3)^2-16
=(x^2+4x)^2+2(x^2+4x)+1-x^2-6x-9-16
=x^4+8x^3+17x^2+2x-24
在整数范围内无法分解因式。
设(x^2+4x)^2+2(x^2+4x)-x^2-6x-24
=(x^2+4x)^2+y(x^2+4x)+y^2/4+(1-y)x^2+(2-4y)-24-y^2/4,①
令(2-4y)^2+(1-y)(96+y^2)
=4-16y+16y^2+96-96y+y^2-y^3
=100-112y+17y^2-y^3=0,
y^3-17y^2+112y-100=0,
取y≈1.049810012,
原式=①=(x^2+4x+0.524905006)^2-0.049810012(x+22.07628507)^2
≈[x^2+4x+0.524905006+0.223181567(x+22.07628507)]
*[x^2+4x+0.524905006-0.223181567(x+22.07628507)].
仅供参考。