Question 698483

When two variables are related in such a way that the ratio of their values always remains the same, the two variables are said to be in direct variation.

In general, we say, that {{{y}}} varies directly as {{{x}}} if there is a constant k so that the equation {{{y=kx}}} is true. 

The {{{slope}}} of a line is the constant of variation. {{{2y=5x+1}}} becomes {{{y=(5/2)x+(1/2)}}}. The constant of variation is {{{5/2}}}, but NO,{{{2y=5x+1}}} is not a {{{direct}}} variation because the equation cannot be written in the form of {{{y=kx}}}. 

if only {{{y=(5/2)x}}}, would be a {{{direct}}} variation, since it has {{{(1/2)}}} added to {{{y=(5/2)x}}}, it's {{{not}}} {{{direct}}} variation