You can 
put this solution on YOUR website! .
y-intercept is the value of  "y"  from the equation, when x= 0.
In your case, y-intercept is
    -5y + 15 = 0
    15  = 5y
     y  = 15/5 = 3.    ANSWER
Solved, answered and explained.
                M E M O R I Z E !
            y-intercept is the value of  " y "  from the equation,  when x= 0.