Describe the error in the subtraction shown below ​ 2 2
(x -4x+3)- (x +7x-9)=3x-6

-11x+12

Step-by-step explanation:

(x^2-4x+3)-(x^2+7x-9)

x^2-x^2-4x-7x+3-(-9)

-11x+3+9

-11x+12

There is no error in the visible part of the subtraction provided. If I'm not mistaken though, I believe I see the start of a truncated equals sign on the right.  I assume by this that you are not including the full image.

As I said though, there is no error in the image provided.   Completing the statement we get:

(x² - 4x + 3) - (x² + 7x - 9) = -11x + 12

stops on an even number.