we are given

we can see that 7 is multiplied with x and y
and we know that
Distribution property:

Here, m is distributed inside (a-b)
While 7 is distributed inside (x-y)
so, we use distributive property
now, we will solve this equation


add both sides 7y


Subtract both sides by 7x


We can see that there is no specific values of x and y for which this equation is defined
so, this equation is identity
so, the solution will be all real numbers.........Answer