I presume you want to find d in this situation. If we start with 4d+1/d+9=-3/-2 we an see this is the same as 4d+1/d+9=3/2 as the negative number cancel to make a positive fraction. Then we can multiply both sides by d+9 to get: 4d+1=3(d+9)/2 We can now multiply both sides by 2 to get: 2(4d+1)=3(d+9) Now expand to get: 8d+2=3d+27 And now take away 3d from both sides to get: 5d+2=27 And now take 2 away from both sides to get: 5d=25 Finally divide both sides by 5 to get: d=5
