y varies directly to x
1. Write an equation
\(y = ax\)
2. Substitute '25' for y and '15' for x
\(25 = a(15)\)
3. Move the variable (a) to the left side of the equation
\(a = 25/15\)
\(y = ( \frac{25}{15})x\)
when x = 6
\(y = (\frac{25}{15}) (6)\)
\(y = \frac{150}{15}\)
\(y = 10\)
