Question

Answer 1

`x^3-7x-6=0`

`<=>x^3-x-6x-6=0`

`<=>x(x-1)(x+1)-6(x+1)=0`

`<=>(x+1)(x^2-x-6)=0`

`<=>(x+1)(x^2+2x-3x-6)=0`

`<=>(x+1)(x+2)(x-3)=0`

`<=>[(x=-1),(x=-2),(x=3):}`

`x^3-4x^2=-4x`

`<=>x(x^2-4x+4)=0`

`<=>x(x-2)^2=0`

`<=>[(x=0),(x=2):}`

`(2x+1)^2=(3+x)^2`

`<=>[(2x+1=x+3),(2x+1=-x+3):}`

`<=>[(x=2),(x=2/3):}`

`x^2+y^2-6x+6y+18=0`

`<=>x^2-6x+9+y^2+6y+9=0`

`<=>(x-3)^2+(y+3)^2=0`

`<=>{(x=3),(y=-3):}`