Too long solution. 3^(x+1) - 3^(x-1) = 3(3^x)-(3^x)/3. Multiplying the whole expression by 3: 9(3^x) - 3^x = 18 8(3^x) = 18 3^x = 9/4 x = log3(9/4) = ln(9/4) / ln(3) = 0.73814… 3^(x+1) = 6.75 3^(x-1) = 0.75 Solved in my head obviously with exception of calculating the actual ternary logarithm of 9/4. Of course, the original solution is more universal.
This's a 8th grade level maths. question of India, Assam...
Logarithms in 8th grade? Where do you live?, I want my kid to study math there!
Too long solution.
3^(x+1) - 3^(x-1) = 3(3^x)-(3^x)/3.
Multiplying the whole expression by 3:
9(3^x) - 3^x = 18
8(3^x) = 18
3^x = 9/4
x = log3(9/4) = ln(9/4) / ln(3) = 0.73814…
3^(x+1) = 6.75
3^(x-1) = 0.75
Solved in my head obviously with exception of calculating the actual ternary logarithm of 9/4.
Of course, the original solution is more universal.
@@rpocc For this, one needs to opt for an alternate subject, called Advanced Maths., which varies from general maths. instead of general knowledge.