Melody

use the site calc on the home page.

Good one Takahiro 

I assume

Let X be the 2000 cpi

135% of X = 228.6

1.35 * X = 228.6

X = 228.6/1.35

and you can finish it.

y=0.02x

that is the answer.

Perhaps you should distribute 20 and -4

like this

 20 (x - y) -4 (x + y)

=20x-20y-4x+-4y

=20x-20y-4x-4y

now collect up the like terms

BE VERY CAREFUL WHEN THERE IS A NEGATIVE NUMBER OR EVEN JUST A NEGATIVE SIGN IN FRONT OF A BRACKET - IT IS VERY EASY TO GET THE SIGN WRONG WHEN YOU EXPAND!

$$\\\frac{2}{3}(\frac{-4x}{3}+1)=-4x-\frac{278}{45}\\\\
\mbox{none of these fractions can be simplified so mult both sides by 45}\\\\
45\left( \frac{2}{3}(\frac{-4x}{3}+1)\right)=45\left(-4x-\frac{278}{45}\right) \\\\
15\left( 2(\frac{-4x}{3}+1)\right)=45\left(-4x-\frac{278}{45}\right) \\\\
30(\frac{-4x}{3}+1)=45*(-4x)-45*\frac{278}{45} \\\\
30*\frac{-4x}{3}+30*1=45*(-4x)-45*\frac{278}{45} \\\\
10*-4x+30=-180x-278 \\\\$$

You should be able to finish it from there.    

Should it be equal to something Zegroes?

I would have answered sooner but I only just saw it.  Sorry.  

I am glad that you are back  

Sorry aziz but that will not get rid of the fractions - not even the algebraic fractions.  

Look here

Aziz is correct but there are some things you may need to know.

The computer symbol of power is ^ and the dot is a times sign *.

So this is how you need to enter it.

(4.29*10^15)*(1.51*10^-4)

oh and the site calc is on the home page.