Question

If a +2b +4c = 0, then āxb +bxc+cxā=
1) 4(bxc) 2) 5(bxc) 3) 6(bxC) 4)7(bxc)​

Answer 1

Answer:

Step-by-step explanation:

Given,

a+2b+3c=0

a=−(2b+3c)

a×a=−(2(b×a)+3(c×a))

⇒0=−(2b×a+3(c×a))..........(i)

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Again,

2b=−(a+3c)

2b×b=−(a×b+3c×b)

⇒0=−(a×b+3c×b)..........(ii)

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equation (i) and (ii)

−(2b×a+3c×a)+(a×b)+3c×b=0

⇒3a×b−3c×a−3b×c=0

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We know that,

a×b=−b×a

a×b=c×a+b×c...............(iii)

Now,ATQ;

a×b+b×c+c×a=Ka×b

1=2a×b=ka×b         {from equation (iii)}

∴k=2

Option C is correct answer.