Show model answer and explanation
3
(17−5)/4.
Class 10 · English Medium · Pearson Edexcel · Mathematics
Ratio, proportion and algebra
Combine rearrangement, inequalities and variation models.
About this lesson and its coverage
Original Kidemy Class 10 progression. This level has its own text, examples and questions. Curriculum versions share the progression; complete board-specific coverage still needs specification matching and additional material.
Learn the idea
Rearranging a formula may involve restrictions such as nonzero divisors. For an inequality, multiplying by a negative reverses order. In a variation model, solve for the constant from a supplied pair before predicting another pair.
Worked example
From v=u+at, a=(v−u)/t for t≠0. For −2x+3≥11, x≤−4.
- Identify the quantities and restrictions.
- Show a method with units or symbols.
- Check and explain the result.
Your written practice
Show your working on paper. Check your answer, then choose Next.
Show model answer and explanation
3
k=30, so y=30/10.
Show model answer and explanation
x+8
3x+6−2x+2.
Write in your own words. A guardian or teacher should review this response.
Show model answer and explanation
x<−3.
Subtract1 and reverse inequality when dividing by −4.
Write in your own words. A guardian or teacher should review this response.
Show model answer and explanation
r=√(A/π), with A≥0.
Select the nonnegative root and state the condition.
Progress and browser storage
Notebook challenge, sources and further study
Apply the idea
Rearrange a science formula and test its restrictions with a numerical example.
Review with a guardian or teacher
- Use the stated evidence or givens.
- Show reasoning rather than only a result.
- Review and explain one correction.
Keep your work on paper or in a local file. This page does not upload it or automatically grade the project.
Teacher-led lessons, schedules and prices for this outline are upcoming. You can use any starter practice above now without booking.
Your next step
Solo practice works without an account. Sign in to save a practice record to your learner profile.
Keep practising
Exact lesson links and related activities are labelled separately. Return-to-course links retain your selected learning path.