If |a|=|b| then (a+b).(a-b) is - Vidyadip

MCQ

If $ |a|=|b| $ then $ (a+b).(a-b) $ is

A
Positive
B
Negative
✓
Zero
D
None of these

✓

Answer

Correct option: C.

Zero

c
(c) $(a + b)\,\,(a - b) = a.a +b.a -b.a - b.b $

$ = a.a - b.b = \,|a{|^2} - |b{|^2}$

$ = 0$ $(\because \,|a|\, = \,|b|)$

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