# Basic Math Question - What went wrong in the following equation?

Let: X=Y

> x+x-x = y+y-y

> 2x-x = 2y-y

> 2x-2y = x-y

> 2(x-y) = x-y

By dividing x-y both side:

> 2=1

What went wrong here?

Relevance
• 9 years ago

since x = y, then x - y = 0. therefore dividing by x - y is dividing by 0.

• cottom
Lv 4
4 years ago

First confirm what number cabinets they are in a position to each and each finished in quarter-hour (a million/3shelf consistent with quarter-hour for Sarah, a million/2 shelf consistent with quarter-hour for Mary). Their mixed fee is then 5/6 shelf consistent with quarter-hour(a million/3 = 2/6, a million/2 = 3/6, 2/6+3/6 = 5/6). Divide the six cabinets via the cabinets they are in a position to end in quarter-hour and multiply it via the quarter-hour to get your answer(6 divided via 5/6 and cases 15 = 108 minutes). it is checked via (108/40 5 * a million) + (108/seventy 5 * 2.5), and the end result ought to be 6 cabinets. I say sorry if I even have erred.

• 9 years ago

At the 4th step, when you divided (x-y) from both sides, you divided by 0, which is undefined.