Posted by Semja on Tuesday, December 13, 2011 at 4:47pm.
How do I approach the following problem. Please don't give answer but just guidance as to how to approach these in general. I need to be able to solve without a calculator.
- Math - Exponentials - bonita, Tuesday, December 13, 2011 at 5:07pm
- Math - Exponentials - Semja , Tuesday, December 13, 2011 at 5:16pm
Eventually answered my own question. No idea what distributing has to do with anything though...
I simplified 3^(2x+1) to ((3^x)^2)*3^x then substituted a variable for 3^x and solved the corresponding quadratic. Seems to have worked
- Math - Exponentials - Reiny, Tuesday, December 13, 2011 at 6:18pm
I think you were on the right track, except
3^(2x+1) = 3(3^x)(3^x) = 3(3^x)^2
so let y = 3^x to change your equation to
3y^2 - 16y + 5 = 0
(y - 5)(3y - 1) = 0
y = 5 or y = 1/3
so 3^x = 5 or 3^x = 1/3
This cannot be solved WITHOUT a calculator
3^x = 5
log 3^x = log 5
x log3 = log 5
x = log5/log3 = appr. 1.465
but 3^x = 1/3
3^x = 3^-1
x = -1
so x = -1 or x = appr. 1.465
both answers verify in the original
Answer this Question
More Related Questions
- General Chemistry - According to the following reaction, how many moles of Fe(OH...
- Math subject Calculus - Hi there I am having some difficulties to solve this ...
- health care 220 - can someone just tell me how to do this I can not get a hold ...
- HCA 220 - I need help with an assignment that is due today and I am totally lost...
- Statistics - The weather forecaster reports that the probability of rain ...
- Math - Is it possible to bend a 20cm length of wire into the shape of a ...
- math concepts - Matthew sits at his desk unable to figure out the answer to a ...
- Math - Hi,I need to know how to do question like this without using a calculator...
- chemistry - What volume of hydrogen gas at standard temperature and pressure can...
- Science - You are a Chemical engineer, trying to synthesize N2H4(l). Your boss ...