Rozwiąż rówania; a)x3-pierw.z 2x2-9x+3pierwiastki z18 =0 b)3x3+x2+48x+16 =0

a) x³ -√2 x² -9x +3√18 = 0 x³ -√2 x² -9x +3 √9*2 = 0 x² -√2 x² -9x + 9 √2 = 0 x*(x² - 9) - √2*(x² -9) = 0 (x - √2)*(x² -9) = 0 (x -√2)*(x - 3)*(x +3) = 0 x1 = -3, x2 = √2, x3 = 3 b) 3x³ + x² + 48 x + 16 = 0 3x*(x² + 16) +(x² + 16) = 0 (3x + 1)*( x² + 16) = 0 <=> 3x +1 = 0 <=> 3x = -1 <=> x = -1/3, ponieważ x² + 16 ≥ 16 > 0 Odp. x = -1/3