5х² = 3х + 2,
5х² - 3х - 2 = 0,
Д = (-3)² - 4 * 5 * (-2) = 9 + 40 = 49,
х1 = (3+7)/2*5 = 10/10 = 1,
х2 = (3-7)/2*5 = -4/10 = -2/5 или -0,4,
х² + 8 + 6х = 0,
х² + 6х + 8 = 0,
Д = 6² - 4 * 1 * 8 = 36 - 32 = 4,
х1 = (-6+2)/2*1 = -4/2 = -2,
х2 = (-6-2)/2*1 = -8/2 = -4