input: Write a function to solve the linear equation a*x + b*y = c for given values of a, b, and c.
  assert linear_eq(3, 5, 7) == (1.0, 0.8)
  assert linear_eq(2, 4, 6) == (1.5, 0.75)
  assert linear_eq(1, 2, 3) == (3.0, 1.5)
output: def linear_eq(a, b, c):
      if a != 0:
          x = c / a
      else:
          x = float('inf')
      if b != 0:
          y = c / b
      else:
          y = float('inf')
      return (x, y)