Melody

There is a calculator on this site and you are using this site!

\(x^2y^2-1 \\\\ =(xy)^2-1^2\\\\ =(xy-1)(xy+1)\)

Come on Namadesto,

We have answered 2 of these questions for you in the last 12 hours.

How about you giving us some of your thoughts on how you might be able to solve it ?

We can talk those through with you if you like :)

Hint:  let y=e^x

You can simplify before or after you do the substitution.  :)

If you double a number and then add 28,you get 4/9 of the original number. What is the original Number?

You should try to give people the opportunity to correct or defend their answer if you think it is wrong. :/

Anyway.

\(2x+28=\frac{4x}{9}\\\\ 9(2x+28)=4x\\\\ 18x+252=4x\\\\ 14x=-252\\\\ x=-252/14\\\\ x=-18\)

Yesterday, Charmaine had 57 baseball cards. Today, she gave c away. Using c , write an expression for the number of cards Charmaine has left.

Ok, this is how you have to think about questions like this.

Say Charmaine had 57 cards and she gave away 6 then she would have   57- 6 cards wouldn't she

Say Charmaine had 57 cards and she gave away 8 then she would have   57- 8 cards wouldn't she

Say Charmaine had 57 cards and she gave away 26 then she would have   57- 26 cards wouldn't she

Say Charmaine had 57 cards and she gave away 19 then she would have   57- 19 cards wouldn't she

Say Charmaine had 57 cards and she gave away c then she would have   57- ? cards 

Just follow the pattern and you can answer the question yourself  

You can tell us what you get if you like and I will tell you if it is correct  :)

ex - 6e-x = 1

\(e^x-6e^{-x}=1\\\\ e^x-\frac{6}{e^{x}}=1\\\\ e^x(e^x-\frac{6}{e^{x}})=1*e^x\\\\ (e^x)^2-6=e^x\\\\ (e^x)^2-e^x-6=0\\\\ sub\;y=e^x\\\\ y^2-y-6=0\\\\ (y-3)(y+2)=0 y=3\;\;or\;\;y=-2\\\\ e^x=3\;\;or\;\;e^x=-2\\\\ lne^x=ln3\;\;or\;\;no\; solution\\\\ x=ln3 \)

how do I do equations

Hi Wolverine :)

Maybe you would like to be more specific.  There are many different equations.

Basically, do must know order of operation,   BODMAS   (or whatever acronym you use)

Then with the equation you get rid of all the things you do not want in the OPPOSITE order to BODMAS (because you are 'undoing' an expression.

ex

3x+7=13

get rid of +7 (I call this a tack on) by subtracting it. BUT if you subtract it from one isde you must subtract it form the other side too

3x+7-7 = 13-7

3x        =  6

Now there is an invisable times sign between the 3 and the x, I'll put that in

3*x=6

I need to get rid of the 3 and the opposite of multiply is divide so I divide by 3 - but I'll have to do it to the other side as well.

(3x)/3=6/3

x       = 2

If that bottom angle is 90 degrees then you have two angles and you can just use angle sum of a triangle.

180-90-45=45 degrees

Otherwise you do not have enough information.  You need to know 3 things about you triangle to find a fourth.

e4x - 5 * e2x = -6 

My answer will be similar I think.

\(e^{4x}-5e^{2x}=6\\\\ (e^{2x})^2-5e^{2x}-6=0\\\\ Sub\;\;y=e^{2x}\\\\ y^2-5y-6=0\\\\ (y-6)(y+1)=0\\\\ y=6\;\;or\;\;y=-1\\\\ e^x=6\;\;or\;\;e^x=-1\\\\ e^x=6\;\;or\;\;no\; solutions\\\\ lne^x=ln6\\\ x=ln6 \)

Answering guest, I think you made a little mistake when you completed the square :)

My 25-450 processor has stopped outputing.  Does anyone have ideas how I can fix it?

Have you tried rebooting it ?

That often works :))