Just a quick (but belated) heads-up:
There's a bug in Chrome version 78.0.3904.70, in which some MathJax images are displaced (and possibly out of view, hence blank). This occurs, for example, in:
Library/Rochester/setLinearAlgebra17DotProductRn/ur_la_17_3.pg
Library/Rochester/setLinearAlgebra17DotProductRn/ur_la_17_4.pg
Library/Rochester/setLinearAlgebra17DotProductRn/ur_la_17_12.pg
Library/Rochester/setLinearAlgebra17DotProductRn/ur_la_17_15.pg
Library/Rochester/setLinearAlgebra18OrthogonalBases/ur_la_18_2.pg
Library/Rochester/setLinearAlgebra18OrthogonalBases/ur_la_18_4.pg
Solution: Upgrade to a newer version of Chrome (78.0.3904.87 works).
Library/Rochester/setLinearAlgebra17DotProductRn/ur_la_17_4.pg
Library/Rochester/setLinearAlgebra17DotProductRn/ur_la_17_12.pg
Library/Rochester/setLinearAlgebra17DotProductRn/ur_la_17_15.pg
Library/Rochester/setLinearAlgebra18OrthogonalBases/ur_la_18_2.pg
Library/Rochester/setLinearAlgebra18OrthogonalBases/ur_la_18_4.pg
Solution: Upgrade to a newer version of Chrome (78.0.3904.87 works).