Answer:
x -7y
Explanation:
7x - 9y - 6x + 2y
Rearrange so like terms are together (these are terms that are similar such as 5b and 7b; 7 and 1)
7x - 6x - 9y + 2y
Group into brackets one-by-one and solve
(7x-6x) -9y + 2y
x -9y + 2y
x (-9y + 2y)
x -7y
Note that 1x, 1b, 1z etc are simply written as their variable eg x, b and z