Question

Answer 1

Bài 3: 

a: =>2x+10-4x=1

=>-2x=-9

=>x=9/2

b: \(\Leftrightarrow\left(x-4\right)\left(5x-2+3\right)=0\)

=>(x-4)(5x+1)=0

=>x=-1/5 hoặc x=4

c: =>(x²-9)=0

=>x=3 hoặc x=-3

Answer 2

Bài `4`:
`a, 5x + 3(x^2-x-1)`

`= 5x + 3x^2 - 3x - 3`

`= 3x^2 + 2x - 3`

`b, (5-x)(5+x) - (2x-1)^2`

`= 25 - x^2 - 4x^2 + 4x - 1`

`= -5x^2 + 4x - 26`

`c, (x^4 + 2x^3 + 10x-25) : (x^2+5)`

`=x^2 + 2x - 5`

Bài `5:`

`x^2 - 9 + 2(x+3)`

`= (x-3)(x+3) + 2(x+3)`

`= (x+3)(x-1)`

`b, x^2 -10x+5 - 3(x-5)`

`= x^2 - 10 x + 5 - 3x + 15`

`= x^2 - 13x + 20`

`c, x^3 - 4x^2 + 3x`

`= x(x^2 - 4x + 3)`

`= x(x-1)(x-3)`