1 способ:1000+1000+500+100+100=2700
2 способ:500+500+1000+500+100+100=2700
28/45 : 63/40=4/9*8/9=32/81
8/15:24=1/15:1/3=1/45
8:4/5=2*5=10
1:7/19= 19/7
1. 3x - 2 > 0
3x > 2
x > 2/3
A = (2/3; +∞)
2. x² + x + 1 > 0
D = 1 - 4 < 0, a > 0 ⇒ x² + x + 1 > 0 при любом x
B = R или (-∞; +∞)
3. X = {-3; -2; -1; 0; 1; 2; 3; 4; 5; 6; 7; 8}
4. M = {5; 6}
5.x² - 5x + 6 = 0
D = 25 - 24 = 1
x₁ = 3
x₂ = 2
С = {2; 3}
6. x² - 3x - 4 ≤ 0
D = 9 + 16 = 25
x₁ = 4
x₂ = -1
------- + ---------- -1 --------- ⁻ --------- 4 --------- + ----------->
Y = [-1; 4]
588:84= 7 (ост. 0) тут без остатка
Очень легко
x+37=85
x=85-37
x=48