3y+5y-3y=6+1/2-9/5+5/4
5y=6+0,5-1,8+1,25
5y=5,95
y=5,95:5
y=1,19
Cos(2П-2x)+3sin(П-x)=2
cos2x + 3sinx = 2
1 - 2sin²x + 3sinx - 2 = 0
2sin²x - 3sinx + 1 = 0
sinx = t
2t² - 3t + 1 = 0
D = 9 - 4*2*1 = 1
t₁ = (3 - 1)/4
t₁ = 1/2
t₂ = (3 + 1)/4
t₂ = 1
1) sinx = 1/2
x = (-1)^n *arcsin(1/2) + πk, k∈Z
x₁ = (-1)^n* (π/6) + πk, k∈Z
2) sinx = 1
x₂ = π/2 + πn, n∈Z
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1\26: 1\2=1,05
1,05-1,5= - 0, 45
- 1 1\9: 3\20= - 1 1\9
- 9\20:(-1 1\9)=1\2
Ответ: 1\2 или 0,5