Cześć!
a)
[tex]2x-(x+3)=6+2x\\\\2x-x-3=6+2x\\\\2x-x-2x=6+3\\\\-x=9 \ \ /:(-1)\\\\\huge\boxed{x=-9}[/tex]
b)
[tex](x-1)(x+3)=x^2-3\\\\x^2+3x-x-3=x^2-3\\\\x^2+2x-3=x^2-3\\\\x^2+2x-x^2=-3+3\\\\2x=0 \ \ /:2\\\\\huge\boxed{x=0}[/tex]
c)
[tex](x+2)(x-2)=x(x-2)\\\\x^2-2x+2x-4=x^2-2x\\\\x^2-4=x^2-2x\\\\x^2-x^2+2x=4\\\\2x=4 \ \ /:2\\\\\huge\boxed{x=2}[/tex]
