1.

Using the identity \[{{a}^{2}}-{{b}^{2}}=(a+b)\,(a-b),\]valuate\[24.7\times 25.3\].

A. \[624.91\]
B. \[642.91\]
C. \[624.19\]
D. \[642.19\]
Answer» B. \[642.91\]


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