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Vayne Mechanics

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Since no one else is really using this thread, I guess I will. I'm doing my review packet for honors Algebra 2. I have the answer key and some of my answers don't match up with the key:
1) -1/2m(-1/2m) -1/2m-1/2m

I got m^4 but the answer key says 1/4m^2-m.
Anyone know how to do this?

I have another question but idk how to type it on the computer so I'm not gonna worry about it.

Edit: Simplify equation, with m being the variable.
violent_anger basically did it, but I'll explain it in my own way because I'm bored.

Ok, so let's rewrite the equation:

[(-1/2m)(-1/2m)] - 1/2m - 1/2m

Now that's done, remember order of operations. First you want to get rid of the brackets, and to do this, you need to multiply. Which ones do you multiply? The bolded portion:
[(-1/2m)(-1/2m)] - 1/2m - 1/2m

Once you do the multiplication, it'll look like this:
1/4m^2 - 1/2m - 1/2m

When you multiply two negatives, the resulting number becomes a positive. This much you should know. Now, when multiplying two fractions, you multiply the numerator of the first by the numerator of the second, and then the denominator of the first by the denominator of the second. So in this example, the first numerator is the number 1, while the second numerator is also 1. Obviously, 1 multiplied by 1 is itself, and so we get 1. Now, the denominator for the first is 2, and similarly, the denominator of the second also happens to be 2. Now, if you remember from way back when, you should realize that 2 multiplied by 2 will result in 4. Thus, our constant becomes 1/4. Now, we also know that when multiplying a variable on itself (i.e. 'a' times 'a', 'x' times 'x'), it becomes the variable squared. In this case, our variable is 'm'. When 'm' is multiplied onto itself, it becomes m^2. Since you can't multiply a constant onto a variable since the variable has no set value yet, we get 1/4m^2.

Onto the next part. Now that we've dealt with that, we still have to worry about this portion:
1/4m^2 - 1/2m - 1/2m

As violent_anger said, "-1/2m - 1/2m simplifies to -2/2m, which again simplifies to -m." If you remember how to add/subtract fractions, this should make perfect sense. After that's all done, our final answer becomes:
1/4m^2 - m

It was probably completely pointless to do this, but whatever.
 

Gatorade

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that last part, -1/2m - 1/2m simplifies to -2/2m, which again simplifies to -m.
As for the first part, -1/2m X -1/2m. -1/2 X -1/2 = 1/4, and m X m is m^2. so, 1/4m^2

1/4m^2 - m



I usually do my math by breaking equations into smaller pieces.

violent_anger basically did it, but I'll explain it in my own way because I'm bored.

Ok, so let's rewrite the equation:
[(-1/2m)(-1/2m)] - 1/2m - 1/2m

Now that's done, remember order of operations. First you want to get rid of the brackets, and to do this, you need to multiply. Which ones do you multiply? The bolded portion:
[(-1/2m)(-1/2m)] - 1/2m - 1/2m

Once you do the multiplication, it'll look like this:
1/4m^2 - 1/2m - 1/2m

When you multiply two negatives, the resulting number becomes a positive. This much you should know. Now, when multiplying two fractions, you multiply the numerator of the first by the numerator of the second, and then the denominator of the first by the denominator of the second. So in this example, the first numerator is the number 1, while the second numerator is also 1. Obviously, 1 multiplied by 1 is itself, and so we get 1. Now, the denominator for the first is 2, and similarly, the denominator of the second also happens to be 2. Now, if you remember from way back when, you should realize that 2 multiplied by 2 will result in 4. Thus, our constant becomes 1/4. Now, we also know that when multiplying a variable on itself (i.e. 'a' times 'a', 'x' times 'x'), it becomes the variable squared. In this case, our variable is 'm'. When 'm' is multiplied onto itself, it becomes m^2. Since you can't multiply a constant onto a variable since the variable has no set value yet, we get 1/4m^2.

Onto the next part. Now that we've dealt with that, we still have to worry about this portion:
1/4m^2 - 1/2m - 1/2m

As violent_anger said, "-1/2m - 1/2m simplifies to -2/2m, which again simplifies to -m." If you remember how to add/subtract fractions, this should make perfect sense. After that's all done, our final answer becomes:
1/4m^2 - m

It was probably completely pointless to do this, but whatever.
Alright, thanks a lot guys. I have midterm exams later today so that's why I have so many questions. I'm still kinda confused on that last part of the equation, but it doesn't matter. Thanks
 

Gatorade

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I don't get this. Can someone explain a little thoroughly?
I'm not sure really how to explain it, but I do know that that's what your supposed to do when trying to find the x-intercept of an equation in slope-intercept form.

You make the y=0 so the y part of the equation is basically non-existent. Then that gives you x and a number and you solve and it gives you the x-intercept. Hope that helps.
 

violent_anger

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y=-4/5x-4

The X intercept means when a line hits the X axis. Confusingly enough, when the line hits the X axis is actually when Y is zero. It's total BS, I know.

so put in zero for Y, and you get 0 = -4/5x - 4. add 4 to both sides, 4 = -4/5x. Now you multiply both sides by -5/4. -4/5 X -5/4 equals 1, while 4 X -5/4 equals -5.

-5 = X.
 

very differentiable
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If it was possible, i would ask you to help me with poems, unfortunately it's in dutch and translating poetry is hard, if not impossible.
 

Nostalgia

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I would really appreciate it if someone could check this over to see if I did it correctly. Thanks in advance. (Btw, ignore that bit at the top).
 

Gatorade

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S5000251.jpg


I would really appreciate it if someone could check this over to see if I did it correctly. Thanks in advance. (Btw, ignore that bit at the top).
I believe that the whole quantity of 8h doesn't go to the bottom. I'm fairly certain that only the h moves into the denominator, which would make the answer (8/h) k^5. Correct me if I am wrong.

And I know you did everything else right, but next to the h^4 on the right hand side of the top line, there should be a negative sign. Everything else seems right to me.
 

Nostalgia

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I believe that the whole quantity of 8h doesn't go to the bottom. I'm fairly certain that only the h moves into the denominator, which would make the answer (8/h) k^5. Correct me if I am wrong.

And I know you did everything else right, but next to the h^4 on the right hand side of the top line, there should be a negative sign. Everything else seems right to me.

I was thinking about what you mentioned in the first part. I grouped 8h with the h on the bottom because I just thought of h as 1h and matched it with a like term, dividing 8 by 1. But, you probably are right; it's unclear. As for the 2nd part about the h^4, I don't understand what you mean.
 

Gatorade

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I was thinking about what you mentioned in the first part. I grouped 8h with the h on the bottom because I just thought of h as 1h and matched it with a like term, dividing 8 by 1. But, you probably are right; it's unclear. As for the 2nd part about the h^4, I don't understand what you mean.
Yeah I actually remember learning in class the other day about how you're supposed to only move the variable down. I'm pretty sure I'm right with that part.

But wait, now I think I did it wrong. See the h^4 in the denominator of your second step of work? Shouldn't that be a negative h^4? Then it would change the whole problem, I think...

I think it would make it (8h^7)(k^5).
 

Nostalgia

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Thanks for the tip, I'll rewrite it that way. As for the h^4, I'm not completely sure, but I thought that since the original was (-h^2)^2, it would be a positive h because I'm multiplying -h by -h along with 2 x 2 for the exponent.
 

Gatorade

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Thanks for the tip, I'll rewrite it that way. As for the h^4, I'm not completely sure, but I thought that since the original was (-h^2)^2, it would be a positive h because I'm multiplying -h by -h along with 2 x 2 for the exponent.
But the thing is, I don't think you are supposed to multiply -h by -h, you're only supposed to mess with the exponent there.
 

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You multiply -1 with itself so you get a positive number.
 

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Ok, I have this chem problem that I have been trying to think of a strategy for and I know it's in my head somewhere but I'm just kind of tired right now and thought I would come here for help.

Anyway the problem says.

True or False? For the reaction represented by the balanced chemical equation.

Mg(OH)2 (aq) + 2HCL (aq) -->2H2O (l) + MgCL2 (aq)

for 0.40 mol of Mg(OH)2, 0.20 mol of HCL will be needed.

and of course show your work after you've chosen whether it is true or false.

*If anything in the chemical equation is unclear just tell me and I'll try to clarify.
 
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