Question

y квадрат-2,6у+1,2=0

Answer 1

y² - 2.6y + 1.2 = 0; | для удобства умножим всё на 10:

10y² - 26y + 12 = 0;

D = 676 - 4 * 10 * 12 = 676 - 480 = 196;

y1 = (26-14)/20 = 12/20 = 6/10 = 0.6

y2 = (26+14)/20 = 40/20 = 2.