In the image, we can see that
five minus a number is matched to S 5 - x
Also, 11 is mached to S on the bottom row.
Hence, we have that
So you will for x, by collecting like terms.
5-x=11
5-11=x
-6=x
Hence x=-6
In the image, we can see that three fewer than a number is matched to G 3-x at the left