Question

if a=2i+3j+4k and b=1i+2j+3k then find(2a-b).(a-2b)​

Answer 1

Explanation:

hope it will help you. do yourself

Answer 2

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$\large\mathcal\red{solution}$

a=2i+3j+4k

b=1i+2j+3k

now...(2a-b)=4i+6j+8k-1i-2j-3k=3i+4j+5k

(a-2b)=2i+3j+4k -2i-4j-6k=-j-2k

(2a-b).(a-2b)=(3i+4j+5k).(-j-2k)

=>(2a-b).(a-2b)=-4-10=-14

$\large\mathcal\red{hope\: this \: helps \:you......}$