Is Goblins free for teachers?

Yes. Goblins offers a generous free tier that includes 1 live feedback assignment per week, insights on student mastery and replays, and the ability to upload your own content. The Max plan adds unlimited assignments, superadaptive mode, grade exports, standards growth reports, and SSO/LMS integration, with per-student pricing for schools and districts.

How does Goblins work?

Three simple steps: (1) Share an assignment from thousands of standards-aligned topics using a share code. (2) Students speak and draw their thinking naturally, and Goblins responds with Socratic questioning that sounds just like their teacher. (3) Teachers get real-time formative insights showing what students struggle with and suggestions to inform instruction.

Does Goblins prevent cheating?

Yes. Goblins uses a purpose-trained AI model that evaluates cheating signals in real time. It can detect when students are copying answers, using external tools inappropriately, or not genuinely working through problems. Copy-pasting answers is also blocked.

Can I use my own voice with Goblins?

Yes. Teachers can record their voice and take a selfie to create a custom 3D avatar in about 30 seconds. Students then hear help in their own teacher's voice and see a familiar face, making the experience more personal and effective.

What math levels does Goblins cover?

Goblins covers math from Grade 5 through AP Calculus, including thousands of standards-aligned topics. Teachers can also upload their own content for custom assignments at any level.

Is Goblins FERPA compliant?

Yes. Goblins is FERPA and state compliant. Student data privacy and security are a top priority.

Does Goblins support English Language Learners?

Yes. Goblins supports 30+ languages so teachers don't have to translate every worksheet. It is especially helpful for ELL students who need accessible math instruction in their native language.

AFM.AQR.5.3

Given a relation on two sets, determine whether the relation is a function and find its inverse relation, if it exists.

Example Problems

What is the inverse of the function?

f(x) = 8x + 1

What is the inverse of the function?

f(x) = 7x + 1

What is the inverse of the function?

f(x) = 5x - 7

Khan Academy Resources

Intro to inverse functions Verifying inverse functions by composition Intro to invertible functions Verify inverse functions Restrict domains of functions to make them invertible Evaluate inverse functions Determine if a function is invertible Find inverses of rational functions Recognize functions from tables Finding inverses of linear functions Recognize functions from graphs Equations vs. functions Intro to inverse functions Finding inverse functions: linear Recognizing functions from table Recognizing functions from graph Obtaining a function from an equation Worked example: matching an input to a function's output (equation)What is the range of a function?Graphing the inverse of a linear function What is a function?Verifying inverse functions by composition Worked example: two inputs with the same output (graph)Finding inverses of rational functions Worked example: evaluating expressions with function notation Restricting domains of functions to make them invertible Does a vertical line represent a function?Worked example: matching an input to a function's output (graph)Determining if a function is invertible Worked example: domain & range of piecewise linear functions What is the domain of a function?Worked example: Evaluating functions from graph Worked example: domain & range of step function Inputs & outputs of inverse functions Verifying inverse functions from tables Recognizing functions from verbal description Recognizing functions from verbal description word problems Verifying inverse functions by composition: not inverse

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