Bonsoir,
(8x+6) + (5x−4) = 8x + 6 + 5x – 4 = 13x + 2
(8x+6) − (5x−4) = 8x + 6 – 5x + 4 = 3x + 10
(8x+6)(5x−4) = 40x² – 32x + 30x – 24 = 40x² – 2x – 24
(8x+6)² + (5x−4)² = (8x)² + 2×8x×6 + 6² + (5x)² – 2×5x×4 + 4² = 64x² + 96x + 36 + 25x² – 40x + 16 = 89x² + 56x + 52