因式分解练习题及答案

1个回答

  • 你可真狠 要这么多题目

    1. 5ax+5bx+3ay+3by

    解法:=5x(a+b)+3y(a+b)

    =(5x+3y)(a+b)

    2. x^3-x^2+x-1

    解法:=(x^3-x^2)+(x-1)

    =x^2(x-1)+ (x-1)

    =(x-1)(x^2+1)

    3. x2-x-y2-y

    解法:=(x2-y2)-(x+y)

    =(x+y)(x-y)-(x+y)

    =(x+y)(x-y-1)

    bc(b+c)+ca(c-a)-ab(a+b)

    =bc(c-a+a+b)+ca(c-a)-ab(a+b)

    =bc(c-a)+bc(a+b)+ca(c-a)-ab(a+b)

    =bc(c-a)+ca(c-a)+bc(a+b)-ab(a+b)

    =(bc+ca)(c-a)+(bc-ab)(a+b)

    =c(c-a)(b+a)+b(a+b)(c-a)

    =(c+b)(c-a)(a+b).

    x^2+3x-40

    =x^2+3x+2.25-42.25

    =(x+1.5)^2-(6.5)^2

    =(x+8)(x-5).

    (x^2+x+1)(x^2+x+2)-12时,可以令y=x^2+x,则

    原式=(y+1)(y+2)-12

    =y^2+3y+2-12=y^2+3y-10

    =(y+5)(y-2)

    =(x^2+x+5)(x^2+x-2)

    =(x^2+x+5)(x+2)(x-1).

    (1+y)^2-2x^2(1+y^2)+x^4(1-y)^2

    原式=(1+y)^2+2(1+y)x^2(1+y)+x^4(1-y)^2-2(1+y)x^2(1-y)-2x^2(1+y^2)

    =[(1+y)+x^2(1-y)]^2-2(1+y)x^2(1-y)-2x^2(1+y^2)

    =[(1+y)+x^2(1-y)]^2-(2x)^2

    =[(1+y)+x^2(1-y)+2x]·[(1+y)+x^2(1-y)-2x]

    =(x^2-x^2y+2x+y+1)(x^2-x^2y-2x+y+1)

    =[(x+1)^2-y(x^2-1)][(x-1)^2-y(x^2-1)]

    =(x+1)(x+1-xy+y)(x-1)(x-1-xy-y)

    x^5+3x^4y-5x^3y^2+4xy^4+12y^5

    原式=(x^5+3x^4y)-(5x^3y^2+15x^2y^3)+(4xy^4+12y^5)

    =x^4(x+3y)-5x^2y^2(x+3y)+4y^4(x+3y)

    =(x+3y)(x^4-5x^2y^2+4y^4)

    =(x+3y)(x^2-4y^2)(x^2-y^2)

    =(x+3y)(x+y)(x-y)(x+2y)(x-2y)

    分解因式m +5n-mn-5m

    m +5n-mn-5m= m -5m -mn+5n

    = (m -5m )+(-mn+5n)

    =m(m-5)-n(m-5)

    =(m-5)(m-n)

    分解因式bc(b+c)+ca(c-a)-ab(a+b)

    bc(b+c)+ca(c-a)-ab(a+b)=bc(c-a+a+b)+ca(c-a)-ab(a+b)

    =bc(c-a)+ca(c-a)+bc(a+b)-ab(a+b)

    =c(c-a)(b+a)+b(a+b)(c-a)

    =(c+b)(c-a)(a+b)

    1.(2a-b)²+8ab

    2.y²-2y-x²+1

    3.x²-xy+yz-xz

    4.6x²+5x-4

    5.2a²-7ab+6b²

    6.(x²-2x)²+2(x²-2x)+1

    7.(x²-2x)²-14(x²-2x)-15

    8.x²(x-y)+(y-x)

    9.169(a+b)²-121(a-b)²

    10.(x-3)(x-5)+1

    答案:1.(2a-b)²+8ab=(2a+b)²

    2.y²-2y-x²+1=(y-1)²-x²=(y-1-x)(y-1+x)

    3.x²-xy+yz-xz =x(x-y)-z(x-y)=(x-z)(x-y)

    4.6x²+5x-4 =(2x-1)(3x+4)

    5.2a²-7ab+6b²=(2a-3b)(a-2b)

    6.(x²-2x)²+2(x²-2x)+1 =(x²-2x+1)²=(x-1)^4

    7.(x²-2x)²-14(x²-2x)-15 =(x²-2x-15)(x²-2x+1)=(x+3)(x-5)(x-1)²

    8.x²(x-y)+(y-x) =(x²-1)(x-y)=(x+1)(x-1)(x-y)

    9.169(a+b)²-121(a-b)²

    =(14a+14b-11a+11b)(14a+14b+11a-11b)

    =(3a+25b)(25a+3b)

    10.(x-3)(x-5)+1 =(x-3)²-2(x-3)+1 =(x-3-1)²=(x-4)²

    -5a^2+16a=a(16-5a)

    8x^2-4x=4x(2x-1)

    15p+10p^2=5p(3+2p)

    -3x^2y-6xy=-3xy(x+2y)

    14m^3n^2-6m^2n^3=2m^2n^2(7m-6n)

    27a^2 b^3 c+18ab^2=9ab^2(3abc+2)

    18xy^2 z^3+12x^2 y^2=6xy^2(3z^3+2x)

    8m^2 n^2 -6m^3 n^2=2m^2 n^2(4-3m)

    因式分解3a3b2c-6a2b2c2+9ab2c3=3ab^2 c(a^2-2ac+3c^2)

    3.因式分解xy+6-2x-3y=(x-3)(y-2)

    4.因式分解x2(x-y)+y2(y-x)=(x+y)(x-y)^2

    5.因式分解2x2-(a-2b)x-ab=(2x-a)(x+b)

    6.因式分解a4-9a2b2=a^2(a+3b)(a-3b)

    7.若已知x3+3x2-4含有x-1的因式,试分解x3+3x2-4=(x-1)(x+2)^2

    8.因式分解ab(x2-y2)+xy(a2-b2)=(ay+bx)(ax-by)

    9.因式分解(x+y)(a-b-c)+(x-y)(b+c-a)=2y(a-b-c)

    10.因式分解a2-a-b2-b=(a+b)(a-b-1)

    11.因式分解(3a-b)2-4(3a-b)(a+3b)+4(a+3b)2=[3a-b-2(a+3b)]^2=(a-7b)^2

    12.因式分解(a+3)2-6(a+3)=(a+3)(a-3)

    13.因式分解(x+1)2(x+2)-(x+1)(x+2)2=-(x+1)(x+2) abc+ab-4a=a(bc+b-4)

    (2)16x2-81=(4x+9)(4x-9)

    (3)9x2-30x+25=(3x-5)^2

    (4)x2-7x-30=(x-10)(x+3)

    35.因式分解x2-25=(x+5)(x-5)

    36.因式分解x2-20x+100=(x-10)^2

    37.因式分解x2+4x+3=(x+1)(x+3)

    38.因式分解4x2-12x+5=(2x-1)(2x-5)

    39.因式分解下列各式: (1)3ax2-6ax=3ax(x-2) (2)x(x+2)-x=x(x+1) (3)x2-4x-ax+4a=(x-4)(x-a) (4)25x2-49=(5x-9)(5x+9) (5)36x2-60x+25=(6x-5)^2 (6)4x2+12x+9=(2x+3)^2 (7)x2-9x+18=(x-3)(x-6) (8)2x2-5x-3=(x-3)(2x+1) (9)12x2-50x+8=2(6x-1)(x-4)

    40.因式分解(x+2)(x-3)+(x+2)(x+4)=(x+2)(2x-1)

    41.因式分解2ax2-3x+2ax-3= (x+1)(2ax-3)

    42.因式分解9x2-66x+121=(3x-11)^2

    43.因式分解8-2x2=2(2+x)(2-x)

    44.因式分解x2-x+14 =整数内无法分解

    45.因式分解9x2-30x+25=(3x-5)^2

    46.因式分解-20x2+9x+20=(-4x+5)(5x+4)

    47.因式分解12x2-29x+15=(4x-3)(3x-5)

    48.因式分解36x2+39x+9=3(3x+1)(4x+3)

    49.因式分解21x2-31x-22=(21x+11)(x-2)

    50.因式分解9x4-35x2-4=(9x^2+1)(x+2)(x-2)

    51.因式分解(2x+1)(x+1)+(2x+1)(x-3)=2(x-1)(2x+1)

    52.因式分解2ax2-3x+2ax-3=(x+1)(2ax-3)

    53.因式分解x(y+2)-x-y-1=(x-1)(y+1)

    54.因式分解(x2-3x)+(x-3)2=(x-3)(2x-3)

    55.因式分解9x2-66x+121=(3x-11)^2

    56.因式分解8-2x2=2(2-x)(2+x)

    57.因式分解x4-1=(x-1)(x+1)(x^2+1)

    58.因式分解x2+4x-xy-2y+4=(x+2)(x-y+2)

    59.因式分解4x2-12x+5=(2x-1)(2x-5)

    60.因式分解21x2-31x-22=(21x+11)(x-2)

    61.因式分解4x2+4xy+y2-4x-2y-3=(2x+y-3)(2x+y+1)

    62.因式分解9x5-35x3-4x=x(9x^2+1)(x+2)(x-2)