Вправи для повторення розділу 3 » 38 (3-4)

3) (x^2- x-20)/(2-x) • (2x- x^2)/(x+4). x2 – x – 20 = 0; D = (–1)2 – 4 • (–20) = 81; x1 = (1+9)/2 = 5; x2 = (1-9)/2 = –4. ((x-5)(x+4) • x(2-x))/((2-x)(x+4)) = (x(x-5))/1 = x2 – 5x. 4) (x+5)/(2x-6) : (x^2+ 11x+30)/(x-3). x2 + 11x + 30 = 0; D = 112 – 4 • 30 = 1; x1 = (-11+1)/2 = –5; x2 = (-11-1)/2 = –6. ((x+5)(x-3))/(2(x-3)(x+5)(x+6)) = 1/(2(x+6)).