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MHT CET202123 Sep 2021Morning ShiftMathematicsVector AlgebraActual

a =4 i +13 j -18 k , b = i -2 j +3 k and c =2 i +3 j -4 k are three vectors such that a =x b +y c , then x+y=

Options

  1. A-1
  2. B-2
  3. C5
  4. D1

Correct answer

D. 1

Step-by-step solution

aligned & a =x b +y c & 4 i +13 j -18 k =( i -2 j +3 k )(x)+(2 i +3 j -4 k )(y) & =(x+2 y) i +(-2 x+3 y) j +(3 x-4 y) k & x+2 y=4,-2 x+3 y=13 and 3 x-4 y=-18 aligned Solving, we get x=-2, y=3 x+y=1

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