Final answer:
The information pertains to solving mathematical expressions using scientific notation and significant figures, typically found in high school mathematics courses.
Step-by-step explanation:
The question appears to be related to solving mathematical expressions using scientific notation and finding the correct number of significant figures. This can be seen from the reference information involving calculations with division, addition, subtraction, and multiplication. Additionally, the mention of a quadratic equation suggests familiarity with algebra is required.
For example, in Exercise 1.9.2 parts (a) and (d), for 217 ÷ 903 and 0.00666 × 321 respectively, you would need to divide and multiply the given numbers and then express the answers in scientific notation with the appropriate significant figures. Similarly, part (b) requires addition and part (c) subtraction, followed by an expression in scientific notation.
In relation to Exercise 2.4.2 and Example 1.9.1, these exercises also require performing arithmetic operations and expressing the answer in scientific notation. Understanding how to properly use significant figures is integral throughout.