Question

If 3^(x+1)+3^(x-1) = 270, what is the value of x ? (Also steps pls)​

Answer 1

Answer:

x=2

Step-by-step explanation:

3

x+1

+3

2x+1

=270.

⇒3.3

x

+3

2x

.3=270

⇒3

x

+3

2x

=90

Substituting 3

x

=a we get a+a

2

=90

⇒a

2

+a−90=0⇒a

2

+10a−9a−90=0

⇒(a+10)(a−9)=0⇒a=9 or a=−10

If 3

x

=9 then x = 2 If 3

x

=−10 which is not possible

∴x=2