You can
put this solution on YOUR website!You can graph the functions and look for regions that go from

to

or vice versa.
These specific functions are discontinuous (undefined) any time the denominator goes to zero.
.
.
.
b)At x=0.
.
.
.

.
.
.
c)At x=0.
.
.
.

.
.
.
d) When x^2+x-6=0,

At x=-3 and at x-2.
.
.
.

.
.
.