translate(tx, ty) can be written as the matrix:
1 0 tx
0 1 ty
0 0 1
scale(sx, sy) can be written as the matrix:
sx 0 0
0 sy 0
0 0 1
rotate(a) can be written as the matrix:
cos(a) -sin(a) 0
sin(a) cos(a) 0
0 0 1
rotate(a, cx, cy) is the combination of translation by (cx, cy), rotation of a degrees and translation back by (-cx, -cy) (source). Multiplying matrices of these transformations results in:
cos(a) -sin(a) -cx × cos(a) + cy × sin(a) + cx
sin(a) cos(a) -cx × sin(a) - cy × cos(a) + cy
0 0 1
If you multiply the translate(tx, ty) matrix with the rotate(a, cx, cy) matrix, you get:
cos(a) -sin(a) -cx × cos(a) + cy × sin(a) + cx + tx
sin(a) cos(a) -cx × sin(a) - cy × cos(a) + cy + ty
0 0 1
Which corresponds to the SVG transform matrix:
(cos(a), sin(a), -sin(a), cos(a), -cx × cos(a) + cy × sin(a) + cx + tx, -cx × sin(a) - cy × cos(a) + cy + ty).
In your case that is: matrix(0.866, -0.5 0.5 0.866 8.84 58.35).
If you include the scale (sx, sy) transform, the matrix is:
(sx × cos(a), sy × sin(a), -sx × sin(a), sy × cos(a), (-cx × cos(a) + cy × sin(a) + cx) × sx + tx, (-cx × sin(a) - cy × cos(a) + cy) × sy + ty)
Note that this assumes you are doing the transformations in the order you wrote them.