Final answer:
To decompose the expression b + b^2, factor out the common term b to get b(b + 1), making option A the correct answer.
Step-by-step explanation:
The student has asked how to decompose the mathematical expression b + b^2. The correct decomposition of this expression is by factoring out the common factor b from both terms. This leads to the expression b(b + 1), which corresponds to option A. To decompose the expression, you identify that b is a common factor in both terms and therefore, you factor it out by using the distributive property (b * 1 + b * b = b + b^2), which simplifies to b(b + 1).