Question

Phân tích các đa thức sau thành nhân tử:

a.x^2 -81

b.x^2-y^2-5(x+y)

c.6x^2-13x +5

d.(x^2 +2x) (x^2+2x -2) -3

xin rủ lòng thương

Answer 1

Answer 2

Answer 3

c, 6x²-13x + 5 = 6x² -3x-10x + 5 =3x(2x-1)-5(2x-1)=(2x-1)(3x-5)

Answer 4

\(a.x^2-81\\ =x^2-9^2\\ =\left(x-9\right)\left(x+9\right)\)

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

\(c.6x^2-13x+5\\ =6x^2-3x-10x+5\\ =3x\left(2x-1\right)-5\left(2x-1\right)\\ =\left(3x-5\right)\left(2x-1\right)\)

Answer 5

Thêm câu d nhé

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

Chúc bạn học tốt