Example

Finding the Difference (9w27w+5)(2w24)(9w^2 - 7w + 5) - (2w^2 - 4)

Find the difference of two polynomials:

(9w27w+5)(2w24)(9w^2 - 7w + 5) - (2w^2 - 4)

Step 1 — Distribute the subtraction and identify like terms: The subtraction sign in front of the second polynomial acts as multiplication by 1-1, changing the sign of every term inside: (2w24)=2w2+4-(2w^2 - 4) = -2w^2 + 4. The expression becomes:

9w27w+52w2+49w^2 - 7w + 5 - 2w^2 + 4

The w2w^2-terms are 9w29w^2 and 2w2-2w^2; 7w-7w has no like-term partner; the constants are 55 and 44.

Step 2 — Rearrange the terms: Group like terms together:

9w22w27w+5+49w^2 - 2w^2 - 7w + 5 + 4

Step 3 — Combine like terms: 92=79 - 2 = 7 gives 7w27w^2; 7w-7w remains unchanged; 5+4=95 + 4 = 9.

The difference is 7w27w+97w^2 - 7w + 9.

The key step that distinguishes polynomial subtraction from addition is distributing the negative sign across the polynomial being subtracted, which flips every term's sign before like terms are combined.

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Updated 2026-04-29

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