The first few steps in deriving the quadratic formula are shown. which best explains why is not added to the left side of the equation in the last step shown in the table? the term is added to the right side of the equation, so it needs to be subtracted from the left side of the equation to balance the sides of the equation. the distributive property needs to be applied to determine the value to add to the left side of the equation to balance the sides of the equation. the term needs to be converted so it has a common denominator before adding it to the left side of the equation to balance the equation. the square root of the term needs to be found before adding the term to the left side of the equation to balance the sides of the equation.

The term b^2 / 4a^2 is not added to the left side of the equation, because the term that was added to the right was not either b^2 / 4 a^2.

As you can see the ther b^2 / 4a^2 that appears in the last step of the table is inside a parenthesis, which is preceded by factor a.

Then, you need to apply the distributive property to know the term that you are really adding to the right side,  i.e. you need to mulitply b^2 / 4a^2 * a which is b^2 / 4a.

That means that you are really adding b^2 / 4a to the right, so that is the same that you have to add to the left, which is what the last step of the table shows.

That situation is reflected by the statement "The distributive property needs to be applied to determine the value to add to the left side of the equation to balance the sides of the equation".  That is the answer.