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初二数学因式分解:若x^3+5x^2+7x+A有一因式x+1,...

您好,(x+1)(x^2+bx+c) =x^3+bx^2+cx+x^2+bx+c =x^3+(b+1)x^2+(b+c)x+c=X^3+5x^2+7x+a 系数对应相等 b+1=5 b+c=7 c=a 解出 b=4,c=a=3 所以a=3 X^3+5x^2+7x+3 =(x+1)(x^2+4x+3) =(x+1)^2(x+3)

解法一: x³-3x²+(a+2)x-2a =x³-3x²+2x+ax-2a =x(x²-3x+2)+a(x-2) =x(x-1)(x-2)+a(x-2) =(x-2)[x(x-1)+a] =(x-2)(x²-x+a) 解法二: x³-3x²+(a+2)x-2a =x³-2x²-x²+(a+2)x-2a =x²(x-...

=x^4+2x²+1 -(x²+2ax+a²) =(x²+1)²-(x+a)² =(x²+1+x+a)(x²+1-x-a)

一般不认为含。要不就乱套了。我算的a是3.

设(x+1)^2=y,那么原式整理后 =[(x+1)^2+1]^2+4[3(x+1)^2+x][2(x+1)^2+(x-1)] =(y+1)^2+4(3y+x)[2y+(x-1)] =y^2+2y+1+4[6y^2+(5x-3)y+x(x-1)] =25y^2+(20x-10)y+4x^2-4x+1 =(5y)^2+10(2x-1)y+(2x-1)^2 =[5y+(2x-1)]^2 =[5(x+1)^2+(2x-1)]^2 =(5x^...

x^5-5x^4+ 8x^3-8x^2 +7x-3 =x^5-3x⁴-2x⁴+6x³+2x³-6x²-2x²+6x+x-3 =x⁴(x-3)-2x³(x-3)+2x²(x-3)-2x(x-3)+(x-3) =(x-3)(x⁴-2x³+2x²-2x+1) =(x-3)【(x⁴-2...

1)原式=2(a^4+b^4-2a²b²)=2(a²-b²)²=2(a+b)²(a-b)² 2)原式=-(16ab+8ab+b²)=-(4a+b)² 3)原式=(x²-5x)²-2(x²-5x)+1=(x²-5x-1)² 4)原式=(m-1)²[4m²-12m+9]=(...

解:①2(x+x)-3(x+x)-2= (x-1)(x+2)(2x^2+2x+1)---------原题目应该错了 ②4x-5x-6= (x-2)(4x+3) 若x-1是x+x+a的一个因式,则a=-2

设多项式的分解结果如下 x³+ax²+bx+8=(x+1)(x+2)(x+m) =(x²+3x+2)(x+m) =x³+(3+m)x²+(3m+2)x+2m 对应系数项相等,有 3+m=a.............(1) 3m+2=b..........(2) 2m=8............(3) 由(3)得,m=4 将m=4代入(1)(2)得...

x³-3x²+5x+a =x²(x-2)-(x²-5x-a) =x²(x-2)-(x-2)(x-3) -a=6 a=-6

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