L = А + В + 0.8B + ⅔A = (5/3)A + 1.8B
A = 60; B = 20
L = 60×5/3 + 1.8×20 = 100 + 36 = 136
9x^2-7x-2=0
D=49-4(9*(-2)=49+72=121
x1 = (7+11)/18=1
x2 = (7-11)/18 = -4/18 = -2/9
Ответ: x1 = 1; x2 = -2/9
А)4х-3х=1 х=1. Б)-х=-13-5 х=18 в)7х+х-6х=8+2 2х=9 х=4.5
207 * 193 = (200 + 7)(200 - 7) = 200² - 7²
18-6^/ (2*3) +3
21-6^/6
7-3^/6
Отв 7-2^/6