18 - 2x^{2} - 5x }18−2x2−5x
Имеет значения при:
}18 - 2x^{2} - 5x 0 \\ - 2 {x}^{2} - 5x + 18 0 \\ 2 {x}^{2} + 5x - 18 \ 0 \\ d = 25 + 8 \ 18 = 169 \\ {d} = 13 \\ x = 2 \\ x = - 4.5\18−2x2−5x⩾0−2x2−5x+18⩾02x2+5x−18⩽0d=25+8×18=169d=13x=2x=−4.5
xє[-4.5;2]
