Cross multiplication of differentials

Is this acceptable at Photomath? I see many people using the same convention. Generally, in problems involving the substitution method in calculus problems, people cross multiply differentials like a normal variable. So, should it be ignored, or should it be returned?

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https://preview.redd.it/c29dyzibrh871.png?width=452&format=png&auto=webp&s=9d5a554bb14a2922e50fc83a5ae53267bb841cf1