53.)

49x-2 = 7Ö 7

a. -5/4
b.5/4
c. 11/4
d. -11/4

79.)

10
E 3n-2
n=4

a. 14+17+20+...+32
b. 28+31+34+...+43
c. 10+13+16+...+28
d. 9+14+17+...+30

66.

ln 1
√e

a. -√e
b. -1/2
c. 1/e
d. 1/2

67.

Solve:
e3x = 8

a. ln 5

b. 3 ln 8

c. ln 8
3

d. ln 3
8

Your questions are incomplete and many contain unexplained symbols.