my most frequently recommended Add-ons for Google Forms, Docs, and Sheets. Last week it was shut down by its own, TextHelp. As a replacement for g(Math) TextHelp recommends their newer product called EquatIO. Unfortunately, while all of EquatIO's features are free for teachers, students need to have a subscription in order to access all of the features within EquatIO. Here are a couple of other Add-ons that you might consider using for inserting graphs and equations into your Google Documents and Google Forms.
Yob Graph Editor allows you to plot data and insert graphs into a Google Doc. It provides plotting and regression functionality inside of your documents. A convenient feature for teachers is that Yob Graph will store your work in Google Drive and let you insert the same graph into multiple documents without having to manually recreate it for each document. This could be helpful when you are trying to make multiple variations of an assignment for students.
Wizkids CAS is another Google Docs Add-on that offers a graphing calculator feature. Wizkids CAS offers tools for solve=ing equations and plotting graphs, finding numerical and exact solutions, and simplifying and factoring expressions with variables. The video embedded below provides an overview of the features in Wizkids CAS.