Question

Pg. 17) If $\sf{2^{x-1}+2^{x+1}=320}$, then find 'x'.​

Answer 1

Answer:

2

x−1

+2

x+1

=320

if x=4 then

2

4−1

+2

4+1

=320

2

3

+2

5

=320

40



=320

if x=5 then

2

5−1

+2

5+1

=320

2

4

+2

6

=320

80



=320

if x=6 then

2

6−1

+2

6+1

=320

2

5

+2

7

=320

160



=320

if x=7 then

2

7−1

+2

7+1

=320

2

6

+2

8

=320

320=320

Hence x=7