My my problem ask solve for one variable (Y)

X-2y=5
(-x+x) -2y=5
(-2y+2y) = -x+5
Y= -x+5+2
Y=-x+7
Am I correct.
Thanks

whatever you do to one side, you must also do to the other side, if they are to remain equal. You subtracted x in your first step, but only on the left.

If you had tried a value for x and y, you would have seen that your solution was wrong.

y = -x+7, so let x=1, and y is -6.
That clearly does not work in the original equation.

Also, -2y+2y is not y, it is zero!

Your steps should have been

x-2y = 5
x-x-2y = 5-x
that gives
-2y = 5-x
now divide by -2 and you have
y = (5-x)/-2 = (x-5)/2