what does ----> mean when someone writes an equation on (in?) yahoo answers please? Very confused....... 5* to top answer!!!XXX?

In a chemical equation, "---->" is an arrow (→) which means "is/are changed to".

In a mathematical expression, the arrow can mean "approaches" or "goes to". For example, lim[x -> 0] (sin(x)/x) or lim(sin(x)/x), x→0 means "the limit of the rational expression sin(x)/x as x approaches zero."

Above a variable, it can designate the variable as a vector. In a logical expression, it might symbolize "implies".

I often see it used here as an equal sign when an expression changes through a series of forms. I do not like that notation, since we already have a perfectly good symbol (=) for that, but I suppose it does no harm. It is used like this:

3x² - 6x + 1
--> 3(x² - 2x) + 1
--> 3(x² - 2x + 1) + 1 - 3(1)
--> 3(x - 1)² - 2

A more reasonable way to use it is to interpret the symbol as saying, "And so it follows that ..." It might then be used to connect equations or other statements that follow one from the other, like this:

x² ≥ 0 for all real x
--> x² + 8 > 0
--> log(x² + 8) is real