Identify Growth Patterns: Analyzing n² + n Expressions in Flower Growth

To solve this problem, we'll evaluate each expression:

• Expression a: $9n^2 + 5n - 8n^2 + 2 - 6n$
  Simplify by combining like terms: $(9n^2 - 8n^2) + (5n - 6n) + 2 = n^2 - n + 2$. This simplification gives a leading positive quadratic term.

• Expression b: $3n + 2$
  It is a linear polynomial, which represents a constant positive growth. Thus, it could model growth, but we will further compare it with others to establish viable growth forms relevant to plant growth requirements.

• Expression c: $n^2 - n + 2$
  Already simplified; exhibits growth as $n$ increases due to the positive leading coefficient of $n^2$.

• Expression d: $1 + n^2 + 2n^2 - 3n^2 + 1$
  Simplify: $(n^2 + 2n^2 - 3n^2) + (1 + 1) = 2$. This simplifies to a constant, not representing increasing growth.

• Expression e: $-5 + 3n^2 - 7n + 4$
  Simplify: $3n^2 - 7n - 1$. Although quadratic and can represent growth, the constant term seems irrelevant for shrub growth understood here.

• Expression f: $9n^2 - 3n - 4$. Already in standard form, offering similar growth properties to “c” in pure quadratic format but compared to a and c it edges. Yet, bears distractions in constants.

The expressions suitable for showing flower growth are those with positive quadratic terms and constant growth interpreted about factors involved in the task relating floral growth to equations suitable. Therefore, expression a and c illustrate this better by showing proper polynomial growth visualized for floristic relevance. Thus, the answer is a, c.