分解因式: 3x2+5xy-2y2+x+9y-4 答案 因为3x2+5xy-2y2=⎛ ⎛⎜ ⎜⎝⎞⎟⎠3x-y⎛ ⎛⎜ ⎜⎝⎞⎟⎠x+2y,所以设3x2+5xy-2y2+x+9y-4=(3x-y+a)(x+2y+b) =3x2+5xy-2y2+ax+2ay+3bx-by+ab =3x2+5xy-2y2+(a+3b)x+(2a-b)y+ab ,所以⎧⎪⎪⎨...
3x2+5xy-2y2+x+9y-4 答案 解:原式=(3x-y)(x+2y)+x+9y-4 =(3x-y)(x+2y)-(3x-y)+4x+8y-4 =(3x-y)(x+2y-1)+4(x+2y-1) =(3x-y+4)(x+2y-1) 故答案为:(3x-y+4)(x+2y-1) 根据因式分解的一般步骤,将前三项运用数字相乘法分解,然后几项进行拆项,提取公因式,就很容易作答...
解答 解:原式=(x+2y)(3x-y)+x+9y-4=(x+2y)(3x-y)+(4x+8y-3x+y)-4=(x+2y)(3x-y)+4(x+2y)-(3x-y)-4=(x+2y)(3x-y)-(3x-y)+4(x+2y)-4=(x+2y-1)(3x-y)+4(x+2y-1)=(x+2y-1)(3x-y+4). 点评 本题考查了分组分解法,正确对式子进行分组,正确利用十字相乘法和项的...
3x²+5xy-2y²+x+9y-4 =(3x-y)(x+2y)+x+9y-4 =(3x-y+4)(x+2y-1)
解答:解:3x2+5xy-2y2+x+9y-4 =(3x-y)(x+2y)+x+9y-4 =(3x-y)(x+2y)-(3x-y)+4x+8y-4 =(3x-y)(x+2y-1)+4(x+2y-1) =(3x-y+4)(x+2y-1). 点评:此题主要考查了因式分解,熟练利用十字相乘法以及拆项法因式分解是解题关键. ...
解:因为 3x^2+5xy-2y^2=(3x-y)(x+2y) , 所以3x2+5xy-2y2+x+9y-4 =(3x-y+a)(x+2y+b) =3x^2+5xy-2y^2+(a+3b)x+(2a-b)y+ab . 比较各项系数得 \(a+3b=12a-b=9. , , 解得a=4,b=-1, 所以原式=(3x-y+4)(x+2y-1).本题是一道因式分解的题目,可以运用分解因 式的意义...
解析 1. (3x-y+4)(x+2y-1)∵3x^2+5xy-2y^2=(3x-y)(x+2y),∴设3x^2+5xy-2y^2-x+9y-4=(3x-y+a)(x+2y+b)=3x^2+5xy-2y^2+(a+3b)x+(2ab-b)y+ab ,比较上式两边系数得a+3b=1 ,2a-b=9 ,ab=-4 ,解之得a=4 ,b=-1 ,∴原式=(3x-y+4)(x+2y-1) . ...
又十字相乘法：先按十字相乘法分解二次项：3X -Y × X 2Y 然后考虑常数项配合进去后，一次项也满足条件：4 3X -Y × X 2Y -1 ∴原式=(3X-Y+4)(X+2Y-1)
解答:解:(1)3x2+5xy-2y2+x+9y-4 =(3x-y)(x+2y)+x+9y-4 =(3x-y)(x+2y)-(3x-y)+4x+8y-4 =(3x-y)(x+2y-1)+4(x+2y-1) =(3x-y+4)(x+2y-1); (2)a3+1=(a+1)(a2-a+1) (3)4x4-13x2+9 =(4x2-9)(x-1) ...
3X^2+5XY-2Y^2+X+9Y-4 =(x+2y)(3x-y)+x+9y-4 =(x+2y)(3x-y)+(4x+8y-3x+y)-4 =(x+2y)(3x-y)+4(x+2y)-(3x-y)-4 =(x+2y)(3x-y) -(3x-y)+4(x+2y) -4 =(x+2y-1)(3x-y)+4(x+2y-1)=(x+2y-1)(3x-y+4)