Question

from the sum of 3 x minus 4 y - 5 z and 5 x + 4 y + 13 z substract x + 2 y - 3 z​

Answer 1

$Let \: A = 3 x - 4 y - 5 z , \: B = 5 x + 4 y + 13 z \\and \: C = x + 2 y - 3 z$

/* According to the problem given */

$A + B - C \\= 3 x - 4 y - 5 z + 5 x + 4 y + 13 z -( x + 2 y - 3 z)$

$= 3 x - 4 y - 5 z + 5 x + 4 y + 13 z -x - 2 y +3 z$

$= 3x + 5x - x - 4y + 4y - 2y - 5z + 13z +3z \\= (3+5-1)x+(-4+4-2)y+(-5+13+3)z \\= 7x -2y +11z$

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