Функция задана формулой y=2x²-x-6 1)Найти y(1),у(-1),у(0). 2)Найти значение х,при которых у(х)=9, у(х)=4, у(х)=15.

Решение задачи:1) y(1) = 2 * 1^2 – 1 – 6 = - 5;y(- 1) = 2 * (- 1)^2 – (- 1) – 6 = 2 + 1 – 6 = - 3;y(0) = 2 * 0^2 – 0 – 6 = - 6.2) a) y(x) = 9.2 * x^2 – x – 6 = 9;2 * x^2 – x – 15 = 0;D = b^2 – 4 * a * c = 121 = 11^2;x1 = (1 – 11) / 4 = - 2.5;x2 = (1 + 11) / 4 = 3.b) y(x) = 4;2 * x^2 – x – 6 = 4;2 * x^2 – x – 10 = 0;D = 81 = 9^2;x1 = (1 – 9) / 4 = - 2;x2 = (1 + 9) / 4 = 2,5.c) y(x) = 15;2 * x^2 – x – 6 = 15;2 * x^2 – x – 21= 0;D = 169 = 13^2;x1 = (1 – 13) / 4 = - 3;x2 = (1 + 13) / 4 = 3,5.