Lời giải:
\(x^6-9x^5+30x^4-45x^3+30x^2-9x+1\)

\(=(x^2)^3-3.(x^2)^2.(3x)+3.x^2(3x)^2-(3x)^3+3x^4-18x^3+30x^2-9x+1\)

\(=(x^2-3x)^3+3x^4-18x^3+30x^2-9x+1\)

\(=(x^2-3x)^3+3(x^4-6x^3+9x^2)+3x^2-9x+1\)

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

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

x³ - 9x² + 7x + 1

= x³ - x2 - 8x² + 8x - x + 1

= (x³ - x²) - (8x² - 8x) - (x - 1)

= x²(x - 1) - 8x(x - 1) - (x - 1)

= (x - 1)(x² - 8x -1)

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

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

\(9x^2+6x-4y^2+4y\)

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

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

1: \(x^2-2x-24=\left(x-6\right)\left(x+4\right)\)

2: \(x^2-8x+15=\left(x-3\right)\left(x-5\right)\)

3: \(x^2-9x+14=\left(x-2\right)\left(x-7\right)\)

x⁴ - 30x² + 31x - 30

= x⁴ + x - 30x² + 30x - 30

= x(x³ + 1) - 30(x² - x + 1)

= x(x + 1)(x² - x + 1) - 30(x² - x + 1)

= (x² - x + 1)[x(x + 1) - 30]

= (x² - x + 1)(x² + x - 30)

= (x² - x + 1)(x² - 5x + 6x - 30)

= (x² - x + 1)[x(x - 5) + 6(x - 5)]

= (x² - x + 1)(x - 5)(x + 6)

4x+5xy-6x+9x²=9x²-2x+5xy=x(9x-2+5y)

hình như đề sai rồi

giúp mk phần a) nha

a) x^2-9x+20

= x^2+4x+5x+20

=(x^2+4x)+(5x+20)

=x(x+4)+5(x+4)

=(x+4)(x+5)