If x 2 +y 2 +z 2 = 121, xyz= 108 and (1/x +1/y + 1/z)=7/9, where x>0,
Right Answer is: B
we know that ,
it is given that 1/x +1/y +1/z =7/9
now putting the values in we get
x+ y+ z= ±17 but negative value of 17 can not be considered here because it is given that x, y and z are greater than zero.
hence x+ y+ z= 17