First change Ax+By=c to y=mx+b
3x+4y=-7
4y=-3x-7
divide by 4
y=-3/4x-7/4
Then want to find the negative reciprocal of -3/4
negative reciprocal slope is: 4/3
After use the point slope formula: y-y1=m(x-x1)
so the point slope that passes (-2,3) and is perpendicular to 3x+4y=-7 is: y-3=4/3(x+2)