Phân tích thành nhân tử :
a, \(x^4+3x^3-7x^2-27x-18\)
b, \(x^4+5x^3-7x^2-41x-30\)
c, \(x^6-14x^4+49x^2-36\)
a) x^3+6x^2+11x+6
b)x^4+3x^3-7x^2+27x-18
c)x^3-8x^2+x+42
d)x^4+5x^3-7x^2-41x-30
c: \(x^3-8x^2+x+42\)
\(=x^3+2x^2-10x^2-20x+21x+42\)
\(=\left(x+2\right)\left(x^2-10x+21\right)\)
\(=\left(x+2\right)\left(x-3\right)\left(x-7\right)\)
a: \(x^3+6x^2+11x+6\)
\(=x^3+3x^2+3x^2+9x+2x+6\)
\(=\left(x+3\right)\left(x^2+3x+2\right)\)
\(=\left(x+3\right)\left(x+1\right)\left(x+2\right)\)
phân tích đa thức thành nhân tử
a, 2x^4-5x^3-27x^2 + 25x + 50
b, 3x^4 + 6x^3- 33x^2-24x+48
c, x^4+ 7x^3+14x^2+14x+4
b) 3x4-3x3+9x3-9x2-24x2+24x-48x+48
=3x3(x-1)+9x2(x-1)-24x(x-1)-48(x-1)
=(x-1)(3x3+9x2-24x-48)
=3(x-1)(x3+3x2-8x-16)
a: x^3-7x-6
=x^3-x-6x-6
=x(x-1)(x+1)-6(x+1)
=(x+1)(x^2-x-6)
=(x-3)(x+2)(x+1)
b: =2x^3+x^2-2x^2-x+6x+3
=x^2(2x+1)-x(2x+1)+3(2x+1)
=(2x+1)(x^2-x+3)
c: =2x^3-3x^2-2x^2+3x+2x-3
=x^2(2x-3)-x(2x-3)+(2x-3)
=(2x-3)(x^2-x+1)
d: =2x^3+x^2+2x^2+x+2x+1
=(2x+1)(x^2+x+1)
e: =3x^3+x^2-3x^2-x+6x+2
=(3x+1)(x^2-x+2)
f: =27x^3-9x^2-18x^2+6x+12x-4
=(3x-1)(9x^2-6x+4)
a) \(x^3-7x-6\)
\(=x^3-x-6x-6\)
\(=\left(x^3-x\right)-\left(6x+6\right)\)
\(=x\left(x^2-1\right)-6\left(x+1\right)\)
\(=x\left(x+1\right)\left(x-1\right)-6\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2-x-6\right)\)
b) \(2x^3-x^2+5x+3\)
\(=2x^3+x^2-2x^2-x+6x+3\)
\(=\left(2x^3+x^2\right)-\left(2x^2+x\right)+\left(6x+3\right)\)
\(=x^2\left(2x+1\right)-x\left(2x+1\right)+3\left(2x+1\right)\)
\(=\left(x^2-x+3\right)\left(2x+1\right)\)
c) \(2x^3-5x^2+5x+1\)
\(=2x^3-3x^2-2x^2+3x+2x-3\)
\(=\left(2x^3-3x^2\right)-\left(2x^2-3x\right)+\left(2x-3\right)\)
\(=x^2\left(2x-3\right)-x\left(2x-3\right)+\left(2x-3\right)\)
\(=\left(x^2-x+1\right)\left(2x-3\right)\)
d) \(2x^3+3x^2+3x+1\)
\(=2x^3+x^2+2x^2+x+2x+1\)
\(=\left(2x^3+x^2\right)+\left(2x^2+x\right)+\left(2x+1\right)\)
\(=x^2\left(2x+1\right)+x\left(2x+1\right)+\left(2x+1\right)\)
\(=\left(2x+1\right)\left(x^2+x+1\right)\)
e) \(3x^3-2x^2+5x+2\)
\(=3x^3+x^2-3x^2-x+6x+2\)
\(=\left(3x^3+x^2\right)-\left(3x^2+x\right)+\left(6x+2\right)\)
\(=x^2\left(3x+1\right)-x\left(3x+1\right)+2\left(3x+1\right)\)
\(=\left(3x-1\right)\left(x^2-x+2\right)\)
f) \(27x^3-27x^2+18x-4\)
\(=27x^3-9x^2-18x^2+6x+12x-4\)
\(=\left(27x^3-9x^2\right)-\left(18x^2-6x\right)+\left(12x-4\right)\)
\(=9x^2\left(3x-1\right)-6x\left(3x-1\right)+4\left(3x-1\right)\)
\(=\left(3x-1\right)\left(9x^2-6x+4\right)\)
Phân tích đa thức thành nhân tử
a, x^3 - 8x^2 +x + 42
b, x^4 + 5x^3 - 7x^2 - 41x - 30
a)x^4+3x^3-7x^2-27x-18
b)x^4+5x^3-7x^2-41x-30
c)x^5-x^4+x^3-x^2+x-1
a) x^4+3x^3-7x^2-27x-18 = x^4+3x^3-3x^2-4x^2-9x-12x-6x-18
= (x^4+3x^3)-(3x^2+9x)-(4x^2+12x)-(6x+18)
= x^3*(x+3)-3x*(x+3)-4x*(x+3)-6(x+3)
= ( x^3-3x-4x-6)*(x+3)
Những câu kia chưa tính ra
Phân tích thành nhân tử:
a) x4+3x3-7x2-27x-18
b) x3-8x2+x+42
c) x4+5x3-7x2-41x-30
a) Ta có: \(x^4+3x^3-7x^2-27x-18\)
\(=x^4-3x^3+6x^3-18x^2+11x^2-33x+6x-18\)
\(=x^3\left(x-3\right)+6x^2\left(x-3\right)+11x\left(x-3\right)+6\left(x-3\right)\)
\(=\left(x-3\right)\left(x^3+6x^2+11x+6\right)\)
\(=\left(x-3\right)\left(x^3+x^2+5x^2+5x+6x+6\right)\)
\(=\left(x-3\right)\left[x^2\left(x+1\right)+5x\left(x+1\right)+6\left(x+1\right)\right]\)
\(=\left(x-3\right)\left(x+1\right)\left(x^2+5x+6\right)\)
\(=\left(x-3\right)\left(x+1\right)\left(x+2\right)\left(x+3\right)\)
b) Ta có: \(x^3-8x^2+x+42\)
\(=x^3-7x^2-x^2+7x-6x+42\)
\(=x^2\left(x-7\right)-x\left(x-7\right)-6\left(x-7\right)\)
\(=\left(x-7\right)\left(x^2-x-6\right)\)
\(=\left(x-7\right)\left(x-3\right)\left(x+2\right)\)
c) Ta có: \(x^4+5x^3-7x^2-41x-30\)
\(=x^4+5x^3-7x^2-35x-6x-30\)
\(=x^3\left(x+5\right)-7x\left(x+5\right)-6\left(x+5\right)\)
\(=\left(x+5\right)\left(x^3-7x-6\right)\)
\(=\left(x+5\right)\left(x^3-x-6x-6\right)\)
\(=\left(x+5\right)\left[x\left(x^2-1\right)-6\left(x+1\right)\right]\)
\(=\left(x+5\right)\left[x\left(x-1\right)\left(x+1\right)-6\left(x+1\right)\right]\)
\(=\left(x+5\right)\left(x+1\right)\left(x^2-x-6\right)\)
\(=\left(x+5\right)\left(x+1\right)\left(x-3\right)\left(x+2\right)\)
a ) \(==>x^3.\left(x+3\right)-\left(7x^2+27x+18\right)\)
ko xét phần x^3.( x+3 ) nữa mà mik phân tích trong ngoặc nha zo thi ko lm như vậy mà ghi lại phần đó nha
\(7x^2+21x+6x+18\)
\(7x\left(x+3\right)+6\left(x+3\right)\)
\(\left(x+3\right)\left(7x+6\right)\)
==> \(x^3.\left(x+3\right)-\left(x+3\right)\left(7x+6\right)\)
==>\(\left(x+3\right)\left(x^3-7x-6\right)\)
Phân tích đa thức thành nhân tử:
a)2x2+3x-27
b)x3-7x+6
c)x3+5x2+8x+4
d)x3-7x-6
e)27x3-27x2+18x-4
\(2x^2+3x-27=2x^2-6x+9x-27=2x\left(x-3\right)+9\left(x-3\right)=\left(2x+9\right)\left(x-3\right)\)
\(x^3-7x+6=x^3-x-6x+6=x\left(x^2-1\right)-6\left(x-1\right)=x\left(x-1\right)\left(x+1\right)-6\left(x-1\right)=\left(x-1\right)\left(x^2+x-6\right)\)
\(x^3+5x^2+8x+4=x^3+x^2+4x^2+8x+4=x^2\left(x+1\right)+4\left(x^2+2x+1\right)=x^2\left(x+1\right)+4\left(x+1\right)^2\)
\(=\left(x+1\right)\left(x^2+4x+4\right)=\left(x+1\right)\left(x+2\right)^2\)
\(27x^3-27x^2+18x-4=27x^3-9x^2-18x^2+6x+12x-4\)
\(=9x^2\left(3x-1\right)-6x\left(3x-1\right)+4\left(3x-1\right)=\left(3x-1\right)\left(9x^2-6x+4\right)\)
Phân tích đa thức thành nhân tử a) x^2 -5x+6 b) 3x^2+9x -30 c)3x^2 -5x-2 d) x^3-7x-6 e) x^4+2x^2+6x-9 f) x^2-7xy+10y^2
\(x^3+6x^2+11x+6\)
\(x^3-8x^2+x+42\)
\(x^4+3x^3-7x^2-27x-18\)
\(x^4+5x^3-7x^2-41x-30\)
a)\(\left(x+1\right)\left(x+2\right)\left(x+3\right)\)
b)\(\left(x-3\right)\left(x-7\right)\left(x+2\right)\)
c)\(\left(x-3\right)\left(x+3\right)\left(x+2\right)\left(x+1\right)\)
d)\(\left(x+5\right)\left(x-3\right)\left(x+1\right)\left(x+2\right)\)
a) x3 + 6x2 + 11x + 6
= (x3 + x2) + (5x2 + 5x) + (6x + 6)
= x2(x + 1) + 5x(x + 1) + 6(x + 1)
= (x2 + 5x + 6)(x + 1)
= (x2 + 2x + 3x + 6)(x + 1)
= [x(x + 2) + 3(x + 2)](x + 1)
= (x + 3)(x + 2)(x + 1)
b) x3 - 8x2 + x + 42
= x3 + 2x2 - 10x2 - 20x + 21x + 42
= x2(x + 2) - 10x(x + 2) + 21(x + 2)
= (x2 - 10x + 21)(x + 2)
= (x2 - 3x - 7x + 21)(x + 2)
=[x(x - 3) - 7(x - 3)](x + 2)
=(x - 7)(x - 3)(x + 2)
c) x4 + 3x3 - 7x2 - 27x - 18
= x4 + x3 + 2x3 + 2x2 - 9x2 - 9x - 18x - 18
= x3(x + 1) + 2x2(x + 1) - 9x(x + 1) - 18(x + 1)
= (x3 + 2x2 - 9x - 18)(x + 1)
= [x2(x + 2) - 9(x + 2)](x + 1)
=(x2 - 9)(x + 2)(x + 1)
= (x - 3)(x + 3)(x + 2)(x + 1)
d) x4 + 5x3 - 7x2 - 41x - 30
= x4 + x3 + 4x3 + 4x2 - 11x2 - 11x - 30x - 30
= x3(x + 1) + 4x2(x + 1) - 11x(x + 1) -30(x + 1)
= (x3 + 4x2 - 11x - 30)(x + 1)
= (x3 + 2x2 + 2x2 + 4x - 15x - 30)(x + 1)
= [x2(x + 2) + 2x(x + 2) - 15(x +2)](x + 1)
=(x2 + 2x - 15)(x + 2)(x + 1)
= (x2 - 3x + 5x - 15)(x + 2)(x +1)
= [x(x - 3) + 5(x - 3)](x + 2)(x + 1)
= (x - 3)(x + 5)(x + 2)(x + 1)
NHỚ TIK CHO MIK NHA, đừng có mà đọc suông xong bỏ đi đấy. mik là đầy đủ hơn cái bn ở dưới nên cho mik nhiều tik hơn nhé