11-6/7-7
is this correct:
11-6=5
7-7=0=
5/0: undefined.
my oh my!!
the way you typed it, it would be
11 - 6/7 - 7
= 77/7 - 6/7 - 49/7
= 22/7
If you meant:
(11-6)/(7-7)
it should be immediately obvious, without even working out the top, that the answer will be undefined since the denominator is zero.