583
б) х² + 11х - 12 = 0
D = b² - 4ac = 11² - 4 * 1 * (-12) = 121 + 48 = 169
D > 0
Х1 = - b - √D / 2a = - 11 - √169 / 2 * 1 = - 11 - 13 / 2 = - 24/2 = - 12
Х2 = - b + √D / 2a = - 11 + √169 / 2 * 1 = - 11 + 13 / 2 = 2/2 = 1
г) х² - 19х + 88 = 0
D = (-19)² - 4 * 1 * 88 = 361 - - 352 = 9
D > 0
Х1 = - (-19) - √9 / 2 * 1 = 19 - 3 / 2 = 16/2 = 8
Х2 = - (-19) + √9 / 2 *1 = 19 + 3 / 2 = 22/22 = 11
584 (б)
х² + 2х - 48 = 0
D = 2² - 4 * 1 * (-48) = 4 + 192 = 196
D > 0
Х1 = - 2 - √196 / 2 * 1 = -2 - 14 / 2 = - 16/2 = - 8
Х2 = -2 + √196 / 2 * 1 = - 2 + 14 / 2 = 12/2 = 6