Question 18296
First, subtract 9 on both sides 

So the equation will becomes -14x = 42, because 51 - 9 = 42
here we left with -14x = 42, and we divide -14 on both sides.
Therefore, it becomes -3, because -14 has a negative sign.

Solution : x = -3

 9-14x=51
 -14x = 42
   x = -3