Question

Which polynomial is to be subtracted from x² + 13x + 7 to get the polynomial 3x² + 5x – 4?

Answer 1

Let the required polynomial be A. 

∴ (x² + 13x + 7) – A = 3x² + 5x – 4 

∴ A = (x² + 13x + 7) – (3x² + 5x – 4) 

= x² + 13x + 7 – 3x² – 5x + 4 

= x² – 3x² + 13x – 5x + 7+4 

= -2x² + 8x + 11

∴ – 2x² + 8x + 11 must be subtracted from x² + 13x + 7 to get 3x² + 5x – 4.