# Algebraic Expression

• Feb 6th 2007, 05:50 PM
Peter
Algebraic Expression
I have absolutely no idea how to work out the algebraic expression(s) to solve this problem.

2 times x is subtracted from 200. The difference is then increased by 20%. If the overall result is equal to decreasing x by 40%, find x.

peter
• Feb 6th 2007, 05:57 PM
Quick
Let's write it out.

Quote:

Originally Posted by Peter
I have absolutely no idea how to work out the algebraic expression(s) to solve this problem.

2 times x is subtracted from 200.

Write it out: $\displaystyle 200-2x$

Quote:

The difference is then increased by 20%.
Write it out again: $\displaystyle 1.2\times\left(200-2x\right)$

Quote:

If the overall result is equal to decreasing x by 40%, find x.
So: $\displaystyle 1.2\times\left(200-2x\right)=0.6x$

Divide both sides by 0.6 to get: $\displaystyle 2\times\left(200-2x\right)=x$

Remove the parenthesis: $\displaystyle 400-4x=x$

Add 4x to both sides: $\displaystyle 400=5x$

Divide both sides by 5: $\displaystyle 80=x$

BUT CHECK MY ARITHMETIC!!!