When using point B, (6,5) = (h,k) y-k=m(x-h) y-5=(3/4)(x-6)
None of the equations using point A's cooridinates for h and k would work because A(-2,-1) has negative values. These negative would alter the subtraction in the equation to addition for example a correct equation for point A would be: y+1=(3/4)(x+2).
The other equation with B's coordinates swapped h and k's places in the equation so it is also in correct.