Question

Answer 1

Bài 2.2: 

\(a,3-x^2\\ =\left(\sqrt{3}\right)^2-x^2\\ =\left(\sqrt{3}-x\right)\left(\sqrt{3}+x\right)\\ b,3-\left(x+1\right)^2\\ =\left(\sqrt{3}\right)^2-\left(x+1\right)^2\\ =\left(\sqrt{3}-x-1\right)\left(\sqrt{3}+x+1\right)\\ c,\left(x+5\right)^2-4x^2\\ =\left(x+5\right)^2-\left(2x\right)^2\\ =\left(x+5-2x\right)\left(x+5+2x\right)\\ =\left(5-x\right)\left(3x+5\right)\\ d,\left(x+1\right)^2-\left(2x-1\right)^2\\ =\left(x+1-2x+1\right)\left(x+1+2x-1\right)\\ =3x\left(2-x\right)\)

Answer 2

bài 1.4

`A = 3x - 3y`

`=> A = 3(x - y)`

`B = 14x^2 - 21xy^2 + 28x^2y^2`

`=> B = 7x(2x - 3y^2 + 4xy^2)`

`C = 2x^2 + 5x^3 + x^2y`

`=> C = x^2. (2 + 5x + y)`

`D = 4x(x - 2y) -8y(x - 2y)`

`=> D = (x - 2y)(4x - 8y)`

`=> D = 4(x - 2y)(x - 2y)`

`=> D = 4(x-2y)^2`