7-1 Additional Practice Adding And Subtracting Polynomials Answer Key < RELIABLE × 2026 >

To Leo, it wasn’t a sheet of paper. It was the wall between a C- and a B+. He’d spent forty-five minutes wrestling with problems like “Add: (3x² + 2x - 5) + (x² - 4x + 7)” and the soul-crushing “Subtract: (5y³ - 2y + 1) - (3y³ + 4y² - y - 6).”

The next morning, she returned the graded practice. Red checkmarks on 1, 3, 4, 5, 6… and a small, perfect check on #7.

His heart thumped. 2y³ - 4y² - y + 7.

He distributed the negative: 5y³ - 3y³ = 2y³. 0y² - 4y² = -4y². -2y - (-y) = -2y + y = -1y. 1 - (-6) = 7.

(5y³ + 0y² - 2y + 1) -(3y³ + 4y² - y - 6) To Leo, it wasn’t a sheet of paper

Now, during the last five minutes of class, Ms. Kellar had stepped into the hall to take a call. The answer key was right there. One quick flip. A single glance.

Ms. Kellar walked back in. “Time’s up. Pass your papers forward.” Red checkmarks on 1, 3, 4, 5, 6…

He imagined the crisp, boxed answers: 1. 4x² - 2x + 2. 2. -2m² + 6m + 1. The certainty of it. No more eraser shavings on his jeans. No more gnawing doubt.