The rest of my response is just for extra clarification
If we assume the second equation is true, then the first would have to be represented as (6 * (1 + 2)) / 2, which is (6 * 3) / 2, which is 18 / 2, which is 9. This means the mistake was made by multiplying the fraction with (1 + 2) by incorrectly placing it in the denominator instead of the numerator. I think the image is supposed to be a tongue-in-cheek troll as the two equations are non-preserving transformations of each other. It's a common mistake that is made in arithmetic.
I just realized where the confusion is coming from:
A fraction written in the formation as shown in the image has implicit parentheses over the numerator and the denominator (as well as the entire fraction) that need to be explicitly written when converted to single-line form.
The rest of my response is just for extra clarification
If we assume the second equation is true, then the first would have to be represented as (6 * (1 + 2)) / 2, which is (6 * 3) / 2, which is 18 / 2, which is 9. This means the mistake was made by multiplying the fraction with (1 + 2) by incorrectly placing it in the denominator instead of the numerator. I think the image is supposed to be a tongue-in-cheek troll as the two equations are non-preserving transformations of each other. It's a common mistake that is made in arithmetic.
Here are the equations in WolframAlpha:
https://www.wolframalpha.com/input?i2d=true&i=Divide%5B6%2C2%5C%2840%291%2B2%5C%2841%29%5D
https://www.wolframalpha.com/input?i2d=true&i=Divide%5B6%2C2%5D%5C%2840%291%2B2%5C%2841%29
Unfortunately the step by step solutions are now locked behind a subscription.