Solve the equation x+y+z =6 2x-y+3z =9 3x+3y-5z = -6

// Plug this in for variable  z  in equation [2]

// Plug this in for variable  z  in equation [3]

// Solve equation [2] for the variable  x 
 

// Plug this in for variable  x  in equation [3]

// Solve equation [3] for the variable  y 

// By now we know this much :

// Use the  y  value to solve for  x 

// Use the  x  and  y  values to solve for  z 
  z = -(1)-(2)+6 = 3 

an advantage of the standard deviation is that it increases as the dispersion of the data increases. e. the interquartile range is preferred when the data are not skewed or no have outliers. an advantage of the standard deviation is that it uses all the observations in its computation.