А+3 а+4
----- ∠ ------
а+4 а+5
(а+3)×(а+5)∠(а+4)×(а+4)
а²+5а+3а+15∠а²+4а+4а+16
а²-а²+5а+3а-4а-4а∠16-15
0∠1
все верно
б)
b₁ = 16√2
q = -√2/2
bₙ = b₁ * qⁿ⁻¹ = 16√2 * (-√2/2)ⁿ⁻¹
b₅ = 16√2 * (√2/2)⁴ = 16√2 * 1/4 = 4√2
г)
b₁ = -√3/3
q = -√3
bₙ = b₁ * qⁿ⁻¹ = -√3/3 * (-√3)ⁿ⁻¹
b₅ = -√3/3 * (-√3)⁴ = -√3/3 * 9 = -3√3
-0.5у=-0.25х-1
0.5у=0.25х+1
у=0.5х+2
|x|=-x
1)x<0 -x=-x
-x+x=0
0x=0
<u> x∈(-∞;0)</u>
2)x≥0 x=-x
x+x=0
2x=0
<u> x=0</u>
x∈(-∞;0)∨{0}=(-∞;0]
Ответ: (-∞;0]