Here's the question you clicked on:
\[\frac{ d ^{2} +d-30}{ d ^{2}+3d-40 }+\frac{ d ^{2}+14d+48 }{ d ^{2}-2d-48 }\]\[\frac{ (d+6)(d-5) }{ (d+8)(d-5) }+\frac{ (d+6)(d+8) }{ (d-8)(d+6) }\]\[\frac{ (d+6)(d-8) }{ (d+8)(d-8) }+\frac{ (d+8)^{2} }{ (d+8)(d-8) }\]\[\frac{ (d ^{2}-2d-48)+(d ^{2}+16d+64) }{ (d+8)(d-8) }\]
I think you can do the rest from here.