8.5 Substitution into expressions and formulae — Practise
Work independently. Questions marked H are for Higher tier.
- Find when .
- Find when .
- Find when and .
- Find when and .
- Find when , and .
- Find when .
- Find when .
- Find when .
Answers and concise solutions
1. Find when .
Answer: .
2. Find when .
Answer: .
3. Find when and .
Answer: .
4. Find when and .
Answer: square units.
5. Find when , and .
Answer: .
6. Find when .
Answer: .
7. Find when .
Answer: .
8. Find when .
Answer: .