10,2х-7,4х+0,88=2
2,8х=2-0,88
2,8х=1,12
х=1,12:2,8
х=0,4
-7 ≤ (2x + 1 )/ 2 < 2
-7 * 2 ≤ 2x + 1 < 2 * 2
-14 ≤ 2x + 1 < 4
-14 -1 ≤ 2x < 4 -1
-15 ≤ 2x < 3
-15/2 ≤ x < 3/2
-7,5 ≤ x < 1,5
Проверка
при x = -7,5:
-7 ≤ (2* (-7,5) + 1 )/ 2 < 2
-7 ≤ (-15 + 1 )/ 2 < 2
-7 ≤ -14/ 2 < 2
-7 ≤ -7 < 2 - истинно
при x = 1:
-7 ≤ (2* 1 + 1 )/ 2 < 2
-7 ≤ (2 + 1 )/ 2 < 2
-7 ≤ 3/ 2 < 2
-7 ≤ 1,5 < 2 - истинно
0,25х<1=х<1:0,25=х<4
<span>0,7х>1,4=х>1,4:0,7=х>2.</span>
1) 850 : 5=170 (км/ч) -общая скорость
2) 170 - 80= 90 - V2
А)
(а³+а⁻⁶) / (а⁻⁴) = a⁴ (a³ + (1/a⁶)) = a⁷ + (a⁴/a⁶)= a⁷ + а⁻²
при а= 10
10⁷ + 10⁻² = 1000000+0,01= 10000000,01
б)
8/(х⁻²) = 8х²
при х=1/2
8 * (1/2)² = 8 * 1/4 = 8/4 = 2
(ab-1) / (bc+1)
при а= -1/2 , b= - 1/3 , с= 1/4
( -1/2 * (-1/3) - 1) /( -1/3 * 1/4 + 1)=
= (1/6 -1) / (-1/12 +1) = (-5/6) : ( 11/12) =
= -5/6 * 12/11 = - (5*2)/(1*11)= -10/11