Dear student, A-B×A+B=A×A+B-B×A+B⇒A-B×A+B=A×A+A×B-B×A+B×BNow, A×A=B×B=0⇒A-B×A+B=A×B-B×A=A×B+A×B⇒A-B×A+B=2A×B Regards

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Dear student,

(A - B) \times (A + B) = (A \times (A + B)) - (B \times (A + B)) \Rightarrow (A - B) \times (A + B) = (A \times A + A \times B) - (B \times A + B \times B) Now, A \times A = B \times B = 0 \Rightarrow (A - B) \times (A + B) = (A \times B) - (B \times A) = (A \times B) + (A \times B) \Rightarrow (A - B) \times (A + B) = 2 (A \times B)

Regards.