Розділ 3. КВАДРАТНІ РІВНЯННЯ » 24.9 (4-6)

4) –x² + 11x – 24. 112 – 4 • (–1) • (–24) = 25; x1 = (-11+5)/(-2 ) = 3; x2 = (-11-5)/(-2) = 8; –x² + 11x – 24 = –(x – 3)(х – 8) = (3 – x)(x – 8). 5) –3x² + 8х + 3. D = 82 – 4 • (–3) • 3 = 100; x1 = (-8+10)/(-6) = –1/3; x2 = (-8-10)/(-6) = 3; –3x² + 8x + 3 = –3(x + 1/3)(x – 3) = (3x + 1)(3 – x). 6) 4x² + x – 3. D = 12 – 4 • 4 • (–3) = 49; x1 = (-1+7)/8 = 3/4; x2 = (-1-7)/8 = –1; 4x² + x – 3 = 4(x – 3/4)(x + 1) = (4x – 3)(х + 1).