Solve 4x - 9 = 15

A. One and one half

B. 6

C. 8

D. 24

I'm pretty sure it's D. I'm just looking for other opinions ...

It's b because negative 9 turns into positive 9 to cancel out the number to isolate variable. Then you also add positive 9 to 15 and that makes 24. But don't forget about 4x which divide into 4x/4 and 24/4 to again isolate the variable. Then 24/4 = 6

4x - 9 = 15

Add 9 on both sides (-9 + 9 cancels out and 15 + 9 = 24)

4x = 24

Divide by 4 on both sides (4 / 4 cancels out and 24 / 4 = 6)

x = 6

The answer is B