Answer:
Did not multiply the numerator by the radical
Step-by-step explanation:
The hypotenuse of a 45-45-90 triangle is equal to the leg times √2.
In this case, the leg is x and the hypotenuse is 6, so we have the following equation
hypotenuse = leg √2
6 = x √2
To solve for x, we get

Then, we need to multiply the numerator and denominator by √2, so

Therefore, the solution is equal to

Therefore, the error in the process was that they did not multiply the numerator by the radical