Luca solved an equation as shown, and verified that his solution was correct. Explain what Luca's error is and why his answer is not completely correct.

Does your response include the following?

Luca did not square the right side of the equation properly.

When the binomial with the radical term is squared, the result still has a radical.

After simplifying, both sides of the equation have to be squared again.

After simplifying, the resulting quadratic trinomial can be solved by factoring.

There are actually two solutions: x = 3 and x = 7.