3x³-7x²+17x-5

=3x³-x²-6x²+2x+15x-5

= x².(3x-1)-2x.(3x-1)+5.(3x-1)

= (3x-1)(x²-2x+5)

Ta có : \(3x^3-7x^2+17x-5\)

    \(=\left(3x^3-x^2\right)-\left(6x^2-2x\right)+\left(15x-5\right)\)

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

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

\(3x^3-7x^2+17x-5.\)

\(=3x^3-x^2-6x^2+2x-15x+5\)

\(=\left(3x^3-x^2\right)-\left(6x^2-2x\right)-\left(15x-5\right)\)

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

a: Ta có: \(-3x^4+20x^3-35x^2-10x+48\)

\(=-\left(3x^4-20x^3+35x^2+10x-48\right)\)

\(=-\left(3x^4-9x^3-11x^3+33x^2+2x^2-6x+16x-48\right)\)

\(=-\left(x-3\right)\left(3x^3-11x^2+2x+16\right)\)

\(=-\left(x-3\right)\left(3x^3-6x^2-5x^2+10x-8x+16\right)\)

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

\(=-\left(x-3\right)\left(x-2\right)\left(3x-8\right)\left(x+1\right)\)

b: Ta có: \(-\left(2x^4+7x^3+x^2-7x-3\right)\)

\(=-\left(2x^4-2x^3+9x^3-9x^2+10x^2-10x+3x-3\right)\)

\(=-\left(x-1\right)\left(2x^3+9x^2+10x+3\right)\)

\(=-\left(x-1\right)\left(2x^3+2x^2+7x^2+7x+3x+3\right)\)

\(=-\left(x-1\right)\left(x+1\right)\left(2x^2+7x+3\right)\)

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

câu b) )Đa thức <=> 
3.x^3 - x^2 - 6x^2 + 2x +15x - 5 
= x^2.(3x - 1) - 2x(3x-1) + 5(3x-1) 
= (3x-1).(x^2 - 2x +5) 

Tick nhé 

a> (x-2)(x^2+x+2)

c ) \(3x^3-7x^2+17x-5\)

\(=3x^3-x^2-6x^2+2x+15x-5\)

\(=\left(3x^3-x^2\right)-\left(6x^2-2x\right)+\left(15x-5\right)\)

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

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

\(4x^3-13x^2+9x-18=4x^3-12x^2-x^2+3x+6x-18\)

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

\(4x^3-13x^2+9x-18\)

\(=4x^3-12x^2-x^2+3x+6x-18\)

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

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

nhẩm nghiệm là gì vậy bạn ?