Question

Martha only kept the positive case when she removed the absolute value. When |A| = B (with B ≥ 0) you must use A = B OR A = −B. She used A = B but omitted A = −B.
Rewrite the above sentence

Answer 1

When removing the absolute value, Martha kept only the positive case: since |A| = B (B ≥ 0) implies A = B or A = −B, she used A = B but omitted A = −B.