The standard form equation for a line is 

in which m represents the slope and b the y-intercept. 
start putting the value of the slope into the equation 

although it is a fraction we repace it as if it was a whole number 
then using (4,5) as (x,y) we can find b, the y-intercept

simplify both sides of the equation 

subtract 1 one on both sides in order to find b 

The equation of the line is 
