1: \(=\left(x+5\right)\left(x-4\right)\)

2: \(=\left(x-5\right)\left(x+4\right)\)

3: \(=2x^2-4x+x-2=\left(x-2\right)\left(2x+1\right)\)

4: \(=3x^2+3x-2x-2\)

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

5: \(4x^2-7x-2\)

\(=4x^2-8x+x-2=\left(x-2\right)\left(4x+1\right)\)

6: \(=4x^2+8x-3x-6=\left(x+2\right)\left(4x-3\right)\)

c,x^4-5x^2+4=x^4-4x^2-x^2+4=(x^2-4)(x^2-1)=(x-1)(x+1)(x-2)(x+2)

e,x^4-3x^3+x^2+3x-2=x^4-x^3-2x^3+2x^2-x^2+x+2x-2=(x-1)(x^3-2x^2-x+2)

Đến đây lấy máy tính bấm Mode*3+1+>+3 rồi tìm nghiệm

Các câu khác cũng máy tính đi

a) co sai de ko

b)x³-2x²+4x²-8x+3x-6=x²(x-2)+4x(x-2)+3(x-2)=(x-2)(x²+4x+3)=(x-2)(x+3)(x+1)

c)x³-2x²+2x²-4x-3x+6=x²(x-2)+2x(x-2)-3(x-2)=(x-2)(x²+2x-3)=(x-2)(x+3)(x-1)

d)x³-3x²+x²-3x-2x+6=x²(x-3)+x(x-3)-2(x-3)=(x-3)(x²+x-2)=(x-3)(x+2)(x-1)

\(16x-5x^2-3\)

\(=-5x^2+16x-3\)

\(=-5x^2+15x+x-3\)

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

\(=-5x.\left(x-3\right)+\left(x-3\right)\)

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

\(2x^2+7x+5\)

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

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

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

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

\(2x^2+3x+5\) (Bạn xem lại đề nhé.)

\(x^3-3x^2+1-3x\)

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

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

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

\(=\left(x+1\right).\left(x^2-4x+1\right)\)

\(x^2-4x-5\)

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

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

\(=x.\left(x-5\right)+\left(x-5\right)\)

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

\(\left(a^2+1\right)^2-4a^2\)

\(=\left(a^2+1\right)^2-\left(2a\right)^2\)

\(=\left(a^2-2a+1\right).\left(a^2+2a+1\right)\)

\(=\left(a-1\right)^2.\left(a+1\right)^2\)

Mình sửa: Bài 1
2)x²+3x-15

a) x² + 6x + 9 = x² + 2 . x . 3 + 3² = (x + 3)²

b) 10x – 25 – x² = -(-10x + 25 +x²) = -(25 – 10x + x²)

                         = -(5² – 2 . 5 . x – x²) = -(5 – x)²

c) 8x³ - 1/8 = (2x)³ – (1/2)³ = (2x - 1/2)[(2x)² + 2x . 12 + (1/2)²]

                    ^{= (2x - 1/2)(4x2 + x + 1/4)} 

d)1/25x² – 64y² = (1/5x)2(1/5x)2- (8y)² = (1/5x + 8y)(1/5x - 8y)

Bài 2

a) 4x(x-3)-3x+9

=4x(x-3)-3(x-3)

= (x-3)(4x-3)

b) x³+2x²-2x-4

=(x³+2x²)-(2x+4)

=x²(x+2)-2(x+2)

=(x+2)(x²-2)

c) 4x²-4y+4y-1

=4x²-1

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

d) x⁵-x

=x(x⁴-1)

=x(x²-1)(x²+1)

a) 4x(x-3)-3x+9

= 4x(x-3) - 3(x-3)

= (x-3)(4x-3)

b)x³ + 2x² - 2x - 4

= x²(x + 2) - 2(x + 2)

= (x+2)(x²-2)

c) 4x² - 4y +4y -1

= [(2x)²-1²] + (-4y+4y)

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

d) x⁵-x

= x(x⁴ - 1)

1)x²-8x-9

= x^2 - 9x +x -9

= x(x+1) - 9 (x+1)

= (x-9) (x+1)

2)x²+3x-18

3)x³-5x²+4x

=x^3 - 4x^2 - x^2 + 4x 

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

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

= x(x-4)(x-1)

4)x³-11x²+30x

5)x³-7x-6

6)x¹⁶-64

\(=\left(x^8\right)^2-8^2\)

\(=\left(x^8-8\right)\left(x^8+8\right)\)

7)x³-5x²+8x-4

8)x²-3x+2

= x^2 - 2x - x +2

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

= (x-2)(x-1)

1)   \(\left(x-9\right)\left(x+1\right)\)             2)   \(\left(x-3\right)\left(x+6\right)\)                                           3)   \(x\left(x-4\right)\left(x-1\right)\)

4)    \(x\left(x-6\right)\left(x-5\right)\)         5)\(\left(x-3\right)\left(x+1\right)\left(x+2\right)\)                               6)   ........

7)  \(\left(x-1\right)\left(x-2\right)\left(x-2\right)\)          8)   \(\left(x-2\right)\left(x-1\right)\)