Welcome to the forum. First, there is no need to write these formulas as images; they can easily be written in text form. For example, the third line of the left image says b = (1c - 5d - 3) / (-5c). It is also a good idea to learn basics of the LaTeX language for writing math formulas that is used on this site. Thus, [tex]b = \frac{1c - 5d - 3}{-5c}[/tex] gives .

The left-hand side in the second line in both images is incorrect.

Concerning multiplying by -1, what one should do (multiply or not) is not a mathematical question. The proper mathematical question is "Is it true or false?" Multiplying both the nominator and the denominator by -1 does not change the value of the fraction, so the claim that is true. That's all mathematics care about. In which form to represent an answer is a matter of aesthetics, not mathematics. (This is a slight exaggeration, but it applies in this case.)

My guess is that, as a matter of style, it is preferable when neither numerator nor denominator start with a minus. In the left image, it is possible to achieve this by rewriting as . In the right image, whether we multiply by -1 or not, either the numerator or the denominator starts with a minus, so we may as well leave them as they are.

The numbers 2a + 2b - 4 and 2b + 2a - 4 are equal. Apparently, you need to select the answer option "up to equality," not "up to the order of terms."