Links
[1] https://www.hootsgo.org/?q=node/6279
[2] http://www.algebrahelp.com/calculators/equation/
[3] http://www.algebrahelp.com/calculators/equation/simplifying/
[4] http://www.algebrahelp.com/calculators/equation/factoring/
[5] http://www.algebrahelp.com/calculators/equation/completingthesquare/
[6] http://www.algebrahelp.com/calculators/function/graphing/
[7] http://www.algebrahelp.com/calculators/equation/3dgraphing/
[8] http://www.algebrahelp.com/calculators/equation/substitution/