Question

What is the correct simplified result of (5x² − 7x + 4) + (−3x² + 5x + 2) − (x² + x + 1)?

Options

• x² − 3x + 5

• x² + 3x + 5

• x² − 3x − 5

• 2x² − 3x + 5

Answer 1

x² − 3x + 5

Explanation:

Combine the first two polynomials, then subtract the third by flipping its signs and combining like terms.

(5x² − 7x + 4) + (−3x² + 5x + 2) −  (x² + x + 1)

= 5x² − 7x + 4 − 3x² + 5x + 2 − x² − x − 1

= 5x² − 3x² − x² − 7x + 5x − x + 4 + 2 − 1

= 5x² − 4x² − 8x + 5x + 6 − 1

= x² − 3x + 5