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