Louisa's three steps are all correct.
Sadly, when she put '56' in place of 'x', the equation says that 11 = 25,
and everybody knows that's not true.
That means that '56' is NOT the solution to the original equation.
(The dot is marked in the correct circle.)
I just looked at the original equation and I tried to solve it in my head.
I got negative 56. Maybe you'd like to check that out.