What is fourteen less than five times a number is three times the number and what is twelve more than seven times a number equals the number less six?

Your first equation:
  5x - 14 = 3x
  5x (- 5x) - 14 = 3x (- 5x)
   - 14 = - 2x
   - 14 (/ - 2) = - 2x (/ - 2)
   7 = x

Your second equation:
    7x + 12 = x - 6
    7x + 12 (+ 6) = x - 6 (+ 6)
    7x + 18 = x
    7x (- 7x) + 18 = x (- 7x)
    18 = - 6x
    18 (/ - 6) = - 6x (/ - 6)
    - 3 = x

I hope this helps :)

Arhombus is a quadrilateral.