Identify the equation which has no solution. 3x - 21 = 3(x + 7) 3x - 21 = 3(x - 7) 3x - 21 = x - 7 All of the choices

3x - 21 = 3(x + 7).

Step-by-step explanation:

3x - 21 = 3(x + 7)

3x - 21 = 3x + 21

3x - 3x = 21 + 21

0 = 42

Since the two are not equal, this equation has no solution.

3x - 21 = 3(x - 7)

3x - 21 = 3x - 21

3x - 3x = -21 + 21

0 = 0

Since the two are equal, this equation has infinitely many solutions.

3x - 21 = x - 7

2x = 14

x = 7

This equation has one solution.

Since there is only one choice that makes sense, the answer won't be all of the choices.

The answer is A. 3x - 21 = 3(x + 7).

Hope this helps!