BBC Compacta is a popular textbook for Class 9 students. It covers various subjects, including English, mathematics, science, and social science. Here is a detailed explanation of each subject and the solutions for the same:

English:
The English section of the BBC Compacta book covers topics like comprehension, grammar, writing skills, and literature. The comprehension passages are based on various themes, including social issues, science, and literature. The grammar section covers various topics like parts of speech, tenses, active and passive voice, direct and indirect speech, etc. The writing skills section focuses on descriptive and narrative writing, letter writing, report writing, and essay writing. The literature section includes various poems, stories, and dramas.

Mathematics:
The mathematics section of the BBC Compacta book covers topics like number systems, algebra, geometry, mensuration, statistics, and probability. The number system includes natural numbers, integers, rational numbers, irrational numbers, and real numbers. The algebraic section covers topics like linear equations, quadratic equations, factorization, etc. The geometry section covers topics like lines and angles, triangles, quadrilaterals, circles, etc. The mensuration section focuses on topics like area, volume, surface area, etc. The statistical section covers topics like mean, median, mode, range, etc. The probability section covers topics like the probability of an event, mutually exclusive events, etc.

Science:
The science section of the BBC Compacta book covers topics like matter, motion, force, work, energy, sound, light, electricity, magnetism, and natural resources. The matter section includes topics like the classification of matter, the states of matter, etc. The motion and force section covers topics like speed, velocity, acceleration, Newton's laws of motion, etc. The work, energy, and power section cover topics like work, energy, power, etc. The sound and light section cover topics like the reflection and refraction of light, the propagation of sound, etc. The electricity and magnetism section cover topics like electric current, potential difference, resistance, etc. The natural resources section covers topics like water resources, mineral resources, forest resources, etc.

Social Science:
The social science section of the BBC Compacta book covers topics like history, geography, economics, and political science. The history section covers topics like the French Revolution, the Industrial Revolution, etc. The geography section covers topics like India's physical features, climate, vegetation, etc. The economics section covers topics like the Indian economy, money and credit, etc. The political science section covers topics like the Indian constitution, democracy, etc.

Conclusion:
In conclusion, BBC Compacta is an excellent textbook for Class 9 students. It covers various subjects and provides detailed explanations of each topic. The solutions provided in the book are comprehensive and easy to understand. It is a must-have book for students who want to excel in their studies.