Question

the expression to be subtracted from(-6x-y+2) to get (x-7y-4)

Answer 1

let the expression be x
(-6x-y+2)-x=(x-7y-4)
(-6x-y+2)-(x-7y-4)=x
-6x-y+2-x+7y+4=x
-7x+6y+6=x
the value of x is the expression to be substracted

Answer 2

Let Required Expression be A

We have, (-6x-y+2) - A = (x-7y-4)
                  So, A = -6x-y+2 -x+7y+4
                        A = -7x+6y+6

So, -7x+6y+6 should be subtracted.