Hello : let
A(15,-25) B(12,-11)
the slope is : (YB - YA)/(XB -XA)
(-11+25)/(12-15) = -14/3
an equation is : y=ax+b a is a slope
y = (-14/3)x +b
the line through point (12,-11) :
-11 = (-14/3)(12)+b
-11 = -56 +b
b = 45
the equation is : y =(-14/3)x+45