`2x^3-72x =0`
`<=> 2x(x^2 - 36) =0`
`TH1 : 2x=0 => x=0`
`Th2 : x^2 -36 =0`
`=>[(x=6),(x=-6):}`
`4x^2 +10x =0`
`<=>2x(2x+5)=0`
`<=>[(2x=0),(2x=-5):}`
`<=> [(x=0),(x=-5/2):}`
`2x(x+3)-x-3=0`
`<=> 2x(x+3)-(x+3)=0`
`<=> (2x-1)(x+3)=0`
`<=> [(2x=1),(x+3=0):}`
`<=> [(x=1/2),(x=-3):}`
`(x-4)^2 +x(x-4) =0`
`<=> (x-4)(x-4+x) =0`
`<=> (x-4)(2x-4) =0`
`<=> [(x-4=0),(2x=4):}`
`<=> [(x=4),(x=2):}`