input: Write a python function to solve a system of linear equations using fsolve.
  assert solve_equation((3, -2, 1, 5)) == [1.66666667, 1.66666667, 1.66666667]
  assert solve_equation((1, 1, 1, 3)) == [1.0, 1.0, 1.0]
output: from scipy.optimize import fsolve
  
  def solve_equation(coefficients):
      def equations(vars):
          x, y, z = vars
          a, b, c, d = coefficients
          return [a*x + b*y + c*z - d,
                  a*x + b*y + c*z - d,
                  a*x + b*y + c*z - d]
      
      solution = fsolve(equations, (1, 1, 1))
      return solution