Question

For which equation is  not a solution? x=-1/3
 A. 7 + 9x = 4 B. 6x – 5 = 7 C. 18+9x=-9
D. 12x + 8 = 4

Answer 1

The answer is B. 
We can prove this by putting -1/3 into x. 
6(-1/3) - 5 = 7 
Multiply -1/3 by 6. 
-2 - 5 = 7 
Subtract 5 from -2. 
-7 $\neq$ 7 
So, -1/3 is not a solution to this equation. 
Hope this helps!