Hey, would you like to help me with my math(s)?

[username n/a]

I have a test tomorrow. I need help with math. I have no idea how to do 1 or 2. For #3 I think you would add logs to both sides and then move the exponent in front of the log... and then I'm lost. For #4 I think you would subtract 82 from both sides, then divide by 15 on both sides... and then I'm lost again. Please help me. I'm trying to get all A's this trimester, and right now I have 3 A's, a C+, and a D+. The D+ is in math. Thank you for your help.

<3Rob

[MakiSupaStar]

The answer is 42.

[username n/a]

Originally Posted by MakiSupaStar

The answer is 42.

Don't you have to go teach English or something?

[MatticusMania]

No.

[nick g.]

On #2, you need to have the same base for both terms. So it should look like:

4^b+1 = 8
2^2(b+1) = 2^3
2(b+1) = 3
2b + 2 = 3
2b = 1
b = 1/2

[irishpride28]

2.) take the log of both sides, like you said. you then have log4^(b+1) = log8
then switch the exponent to become a coefficient. then divide everything by log4 to isolate (b+1). Since dividing logs is written the same way as subtracting them, i THINK it should go as follows for the final answer
b = (log8-log4) -1

I could be wrong.

[Jim Nazium]

1. x^logx(12^(1/4)) = x^(1/4)
=> 12^(1/4) = x^(1/4)
=> x=12

2. 4^(b+1) = 8
=> 4*4^b = 8
=> 4^b = 2
=> 2^b * 2^b = 2
=> (2^b)^2 = 2
=> 2^2b = 2
=> 2b = 1
=> b = 1/2

[tastybasslines]

Originally Posted by MakiSupaStar

The answer is 42.

Mark King answered this problem.

[Jim Nazium]

3. (x-5.1)^4 = 256
=> x-5.1 = 256^(1/4)
=> x-5.1 = (2^8)^(1/4)
=> x-5.1 = 2^2 = 4
=> x = 9.1

[MakiSupaStar]

Originally Posted by username n/a

Don't you have to go teach English or something?

Don't you have to go do your homework or something?

[Jim Nazium]

4. 82 + 15(1.5)^x = 100
=> 15(1.5)^x = 18
=> 1.5^x = 18/15 = 6/5
=> x = log[base 1.5](6/5)
best I can do with that one

[MatticusMania]

I will be emailing your Math teacher to let him/her know that you are having people on the internet do your homework fo you.

[jmattbassplaya]

The day before the test? You obviously don't know how to study math lol

[L-A]

If you find the solution by yourself, you'll remember it tomorrow during the test.

[Atoz]

Originally Posted by Jim Nazium

4. 82 + 15(1.5)^x = 100
=> 15(1.5)^x = 18
=> 1.5^x = 18/15 = 6/5
=> x = log[base 1.5](6/5)
best I can do with that one

Since log_1.5(6/5) = log₁₀(6/5)/log₁₀(1.5), you can get an actual number with your calculator if you need it.

[Chebass88]

Username - as some answers have already been shared, the most important thing to know HOW to do the problems.

Math is exceptionally logical. Any given mathematical operation can be undone by its opposite. Addition is the "opposite" of subtration. Multiplication is the "opposite" of division. A root or logarithm is the "opposite" of an exponent. Also, you can do anything you want to an equation, provided you do the same to both sides. So, if you subtract 3 from the left side, subtract 3 from the right side. If you take the cube root of the left side, take the cube root of the right side. That's pretty much all there is to algebra.

Follow Jim Nazium's answer for #3:

3. (x-5.1)^4 = 256
=> x-5.1 = 256^(1/4)
=> x-5.1 = (2^8)^(1/4)
=> x-5.1 = 2^2 = 4
=> x = 9.1

To isolate the x, take the 4th root of both sides.
(x-5.1)⁴ = 256

((x-5.1)⁴)^1/4 = 256^1/4

There is a rule of exponents that states: (x^a)^b = x^ab

In this case, a = 4 & b = 1/4, so

(x-5.1)^4/4=256^1/4

4/4 = 1, and

(x-5.1)¹=(x-5.1)

So, x-5.1 = 256^1/4

256 = 16*16 = 4² * 4² = 4²⁺² = 4⁴ because of the exponent rule x^a * x^b = x^a+b

(4⁴)^1/4 = 4^4/4 = 4¹

(Jim wrote this as (2⁸)^1/4, which makes the math similar. Either way is fine)

SO,

x-5.1 = 4

Add 5.1 to both sides

x - 5.1 + 5.1 = 4 + 5.1

x -0 = 9.1

x = 9.1

Apply the same sort of analysis to all of the other problems & you'll be fine.

Work through additional problems like this from your textbook (WITHOUT just getting the answers from TB!!!), and you should be able to do well tomorrow. If you need more help, send a PM.

ian

[Ziltoid]

Wolfgram alpha, thank me later. They actually explain the crap and make you visualize it.

Also people only gave you half of the answer for #3. The other being 1.1.

[Chebass88]

Originally Posted by Ziltoid

Wolfgram alpha, thank me later. They actually explain the crap and make you visualize it.

Also people only gave you half of the answer for #3. The other being 1.1.

Yes. Sorry about that. **Covers head with blanket of mathematical shame**

[Topspin]

Originally Posted by MatticusMania

No.

+1

I have no idea anyway.

[machine gewehr]

Originally Posted by jmattbassplaya

The day before the test? You obviously don't know how to study math lol

Exactly.

Relax boy,you'll have plenty of time to study after you wake up in the morning.