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.

What grade level is AII-A.REI.2 taught?

This standard is part of the AII-A curriculum in New York State Next Generation Mathematics Learning Standards.

Are there practice problems for AII-A.REI.2?

Yes, there are 3 practice problems available for AII-A.REI.2 with worked examples.

What learning resources are available for AII-A.REI.2?

There are 24 Khan Academy resources available for AII-A.REI.2, including 15 videos, 6 exercises, 3 articles.

AII-A.REI.2: Solve rational and radical equations in one variable, identify extraneous solutions, and explain how they arise. | Next Gen

Solve rational and radical equations in one variable, identify extraneous solutions, and explain how they arise.

Example Problems

Solve for x:

\frac{4x}{x + 1} = 2

Solve for x:

\frac{1}{2x + 1} = 5

Solve for x:

\frac{3x - 2}{3x + 1} = 3

Khan Academy Resources

Extraneous solutions of radical equations Intro to solving square-root equations Solving square-root equations Rational equations intro Square-root equations Square-root equations intro Rational equations Extraneous solutions of equations Find inverses of rational functions Rational equations intro Solving square-root equations: one solution Intro to square-root equations & extraneous solutions Solving cube-root equations Rational equations word problem: combined rates (example 2)Rational equations word problem: eliminating solutions Rational equations word problem: combined rates Equation that has a specific extraneous solution Finding inverses of rational functions Equations with rational expressions Solving square-root equations: no solution Equations with rational expressions (example 2)Extraneous solutions Solving square-root equations: two solutions Square-root equations intro

1-on-1 AI tutoring aligned to AII-A.REI.2. Instant help for students, real-time insights for teachers.

Used in classrooms by 100,000+ students at Baltimore County, Plano ISD, Deer Valley USD, KIPP, and districts nationwide.

Free for teachers, forever →