A2.A.SSE.A.1b · Reteach Notes

Interpreting Parts of Complex Expressions

Learning TargetI can identify and explain the meaning of specific parts of a complex expression within a real-world context.

Three-Question Strategy

Before answering, ask yourself:
  1. What does the WHOLE expression model? (what is the output?)
  2. What is the VARIABLE? (what is changing?)
  3. NOW identify the specific part being asked about — in context.

Example 1 — Exponential Growth Model

B = 2500(1.04)^t (bank account, t = years). What does 1.04 represent?

2500 = starting balance (t = 0)value at the beginning

1.04 = 1 + 0.04100% kept + 4% added each year

1.04 is the annual growth factor. The account grows by 4% per year.

Example 2 — Linear Context

C = 75 + 55h (plumber, h = hours). What does 55 represent?

75 = flat fee (h = 0)cost even with zero hours

55 = multiplied by ha rate — cost per unit of h

55 is the hourly rate — the plumber charges $55 per hour of work.

Try It First — then check DeltaMath

1. V = 24000(0.88)^n (car value after n years). What does 0.88 represent?

2. P = −3x² + 120x − 500 (profit, x = hundreds of items). What does −500 represent?

Answers: 1) depreciation factor — car retains 88% of value each year (loses 12%) 2) fixed costs / overhead — the loss when no items are sold

Now complete your DeltaMath assignment: Interpreting Parts of an Expression · Interpreting Expressions in Context