17) f(x) 1 lim f(x) x+2 x-+-2 -6In the exercise below, the initial substitution of x = a yields the form 0/0. Look for ways to simplify the function algebraically, or use a table and/or graph to determine the limit. When necessary, state that the limit does not exist. 18) lim x2 - 64 x--8 x+8Determine the continuity of the function at the given points. for x = =1 19) f(x) = 1- 1 X2 - 2, for x = -1 atx= -1 and x =0 2 /2 3 4 x Evaluate or determine that the limit does not exist for each of the limits (a) lim f(x), (b) lim f(x), and (c) lim f(x) x-d- x-+d+ x-+d for the given function f and number d. 2x - 3, for x 1