Question

Phân tích đa thức thành nhân tử:

2x^2 - 13x - 24

3x^2 + 16x + 5
15x^2 + x - 28
35x^2 - 18y^2 + 83xy
6x^2 - 7x - 49
15x^2 - 22x - 5
2x^2 - 3x - 9

Answer 1

*) \(2x^2-13x-24=2x^2+3x-16x-24\)

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

*) \(3x^2+16x+5=3x^2+x+15x+5\)

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

*) \(15x^2+x-28=15x^2-20x+21x-28\)

\(=5x\left(3x-4\right)+7\left(3x-4\right)=\left(5x+7\right)\left(3x-4\right)\)

*) \(35x^2-18y^2+83xy=35x^2-7xy+90xy-18y^2\)

\(=7x\left(5x-y\right)+18y\left(5x-y\right)=\left(7x+18y\right)\left(5x-y\right)\)

*) \(6x^2-7x-49=6x^2+14x-21x-49\)

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

*) \(15x^2-22x-5=15x^2+3x-25x-5\)

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

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

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