Answer:
(a) -7
(b) 7
(c) DNE
Explanation:
(a) lim f(x) x -->0-
= lim 7 (-x) / x
= -7
(b) lim f(x) x -->0+
= lim 7y / y
= 7
(c) lim f(x) ≠ lim f(x)
≠: does not equal sign
x -->0- ≠ x -->0+
so lim f(x) x -->0 = does not exist
look at the pictures if you don't understand