Hi Nana;
I am assuming that...
y=3(x)=b
is
y=3xb
Henceforth, the slope is 3.
I am assuming that...
(5,25) (0,40)
are coordinates, (x,y)
Slope=(y_{2}_{ }y_{1})/(x_{2}  x_{1})
Slope=(4025)/(05)
Slope=15/5
Slope=3
Please recheck the equation...
y=3(x)=b
should indicate the slope as 3, not 3.
10/3/2013

Vivian L.