`(x-1)^2 - (x-1)(x-2) =3`
`<=> x^2 -2x +1 - (x^2 -2x -x +2) -3 =0`
`<=> x^2 -2x+1-x^2 +2x +x -2 -3 =0`
`<=> x -4 =0`
`<=> x=4`
`(2x-3)^2 -(2x-3)(2x+3) =7`
`<=> (2x-3)(2x-3-2x-3) =7`
`<=> (2x-3)*(-6)=7`
`<=> 2x-3 = -7/6`
`<=> 2x = -7/6 +3 =11/6`
`<=> x = 11/6 : 2 = 11/12`
