GeoGebra Book (online)  Solving Equations: Mapping Diagram Visualization HBS 2019 https://www.geogebra.org/m/suckpqju 

Mapping Diagram Sheets 
Mapping
Diagram blanks (2 axis diagrams) 
Mapping
Diagram blanks (2 and 3 axes) 
Work/Spread sheets 
MD Worksheet 
Spreadsheet
Template (Linear
Functions) Spreadsheet Template (Quadratic Functions) 
Sections from MD from A B to C and DE (Drafts)  Visualizing
Functions: An Overview References 
Linear
Functions (LF) Quadratic Functions(QF) 
YouTube Videos 
Using Mapping Diagrams to Visualize Linear Functions (10 Minutes)Solving Linear Equations Visualized with Mapping Diagrams.

"Concepts
to Drive Technology in the 21st Century" (html),
ComputerBasedMath
™(YouTube Video) (CBM) Education
Summit, UNICEF, NYC, Nov.22 ,2013. Using Mapping Diagrams to Understand Functions 