a) \(x^3+4x^2-21x\)

\(=x\left(x^2+4x-21\right)\)

\(=x\left(x^2-3x+7x-21\right)\)

\(=x\left[x\left(x-3\right)+7\left(x-3\right)\right]\)

\(=x\left(x-3\right)\left(x+7\right)\)

b) \(5x^3+6x^2+x\)

\(=x\left(5x^2+6x+1\right)\)

\(=x\left(5x^2+5x+x+1\right)\)

\(=x\left[5x\left(x+1\right)+\left(x+1\right)\right]\)

\(=x\left(x+1\right)\left(5x+1\right)\)

c) \(x^3-7x+6\)

\(=x^3+2x^2-3x-2x^2-4x+6\)

\(=x\left(x^2+2x-3\right)-2\left(x^2+2x-3\right)\)

\(=\left(x-2\right)\left(x^2+2x-3\right)\)

\(=\left(x-2\right)\left(x-1\right)\left(x+3\right)\)

d) \(3x^3+2x-5\)

\(=3x^3+3x^2+5x-3x^2-3x-5\)

\(=x\left(3x^2+3x+5\right)-\left(3x^2+3x+5\right)\)

\(=\left(x-1\right)\left(3x^2+3x+5\right)\)

x³-3x²-4=

a)3x²+7x-6

=3x²-2x+9x-6

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

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

b)8x²-2x-3

=8x²-6x+4x-3

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

=(2x+1)(4x-3)

c)6x²-15x+6

=3(2x²-5x+2)

=3(2x²-x-4x+2)

=3[x(2x-1)-2(2x-1)]

=3(x-2)(2x-1)

d)10x²+7x-6

=10x²+12x-5x-6

=2x(5x+6)-(5x+6)

=(2x-1)(5x+6)

a, 3x^2 + 13x + 10  

= 3x^2 + 3x + 10x + 10 

= 3x(x + 1) + 10(x + 1)

= (3x + 10)(x + 1)

b, x^2 - 10x + 21

= x^2 - 3x - 7x + 21

= x(x - 3) - 7(x - 3)

= (x - 7)(x - 3)

c, 6x^2 - 5x + 1

= 6x^2 - 3x - 2x + 1

= 3x(2x - 1) - (2x - 1)

= (3x - 1)(2x - 1)

Bạn đăng 1 lần nhiều bài như vậy làm người khác nản lắm đấy =) đơn giản bài rất dài mà mik cx ko chắc là bản thân mik có đc k hay ko nên phải nản vậy thôi :)

1a)\(3x^2+13x+10=3x^2+3x+10x+10\)

\(3x\left(x+1\right)+10\left(x+1\right)=\left(3x+10\right)\left(x+1\right)\)

b)\(x^2-10x+21=x^2-3x-7x+21\)

\(=x\left(x-3\right)-7\left(x-3\right)=\left(x-7\right)\left(x-3\right)\)

c)\(6x^2-5x+1=6x^2-3x-2x+1\)

\(=3x\left(2x-1\right)-\left(2x-1\right)=\left(3x-1\right)\left(2x-1\right)\)

1,

\(a,3x^2+13x+10=3x^2+3x+10x+10\)

\(=3x\left(x+1\right)+10\left(x+1\right)\)

\(=\left(x+1\right)\left(3x+10\right)\)

\(b,x^2-10x+21=x^2-7x-3x+21\)

\(=x\left(x-7\right)-3\left(x-7\right)\)

\(=\left(x-7\right)\left(x-3\right)\)

\(c,6x^2-5x+1=6x^2-2x-3x+1\)

\(=2x\left(3x-1\right)-\left(3x-1\right)\)

\(=\left(3x-1\right)\left(2x-1\right)\)

2,

\(a,x^8+4=\left(x^4\right)^2+4x^4+2^2-4x^4\)

\(=\left(x^4+2\right)^2-4x^4\)

\(=\left(x^4+2-2x^2\right)\left(x^4+2+2x^2\right)\)

\(b,x^4+18^2=\left(x^2\right)^2+36x^2+18^2-36x^2\)

\(=\left(x^2+18\right)-36x^2\)

\(=\left(x^2+18-6x\right)\left(x^2+18+6x\right)\)

\(c,x^4+3x^2+4=x^4+4x^2+4-x^2\)

\(=\left(x^2+2\right)-x^2\)

\(=\left(x^2+2-x\right)\left(x^2+2+x\right)\)

Toán Học Team 

a) Ta có : x² + 7x + 12 

= x² + 3x + 4x + 12

= (x² + 3x) + (4x + 12)

= x(x + 3) + 4(x + 3)

= (x + 4)(x + 3)

Bạn ơi mk nhầm đề rồi số 30 thay bằng số 60 còn 36 thay bằng 72 và 39 thay bằng 75 nha 

Ta có \(x^2+7x+12\)

=\(x^2+3x+4x+12\)

=\(\left(x^2+3x\right)+\left(4x+12\right)\)

=\(x\left(x+3\right)+4\left(x+3\right)\)

=\(\left(x+4\right)\left(x+3\right)\)

a) \(=x^2-2x-4x+8\)

\(=x\left(x-2\right)-4\left(x-2\right)\)

\(=\left(x-2\right)\left(x-4\right)\)

c) \(=x^3-x-6x-6\)

\(=x\left(x^2-1\right)-6\left(x+1\right)\)

\(=x\left(x+1\right)\left(x-1\right)-6\left(x+1\right)\)

\(=x\left(x+1\right)\left(x-1-6\right)\)

\(=x\left(x+1\right)\left(x-7\right)\)

khó quá mk nản chí rùi huhu!!

3463465655775676876897756232544545465657578768

b,tách x=-2x+x

1/  \(2x^2+3x-5=\left(2x^2+2x\right)-\left(5x+5\right)=2x\left(x+1\right)-5\left(x+1\right)=\left(x+1\right)\left(2x-5\right)\)

2/ \(16x-5x^2-3=\left(15x-5x^2\right)+\left(x-3\right)=5x\left(3-x\right)-\left(3-x\right)=\left(3-x\right)\left(5x-1\right)\)

3/ \(7x-6x^2-2=\left(3x-6x^2\right)-\left(2-4x\right)=3x\left(1-2x\right)-2\left(1-2x\right)=\left(1-2x\right)\left(3x-2\right)\)

4/ \(x^2+5x-6=\left(x^2-x\right)+\left(6x-6\right)=x\left(x-1\right)+6\left(x-1\right)=\left(x-1\right)\left(x+6\right)\)

a) 8x² - 2x - 1

=8x²+2x-4x-1

=2x.(4x+1)-(4x+1)

=(4x+1)(2x-1)

b) x² - y² + 10x - 6y + 16

=x²+10x+25-y²-6y-9

=(x+5)²-(y+3)²

=(x+5-y-3)(x+5+y+3)

=(x-y+2)(x+y+8)