(а-b)^2=a^2-2ab+b^2
(5a-4b^2)^2=25a^2-40ab^2+16b^4
-3(x^4-2x^2+1)=-3(x^2-1)^2
Z₁ + z₂ = 5 + 2i + 2 - i = (5 + 2) + i(2 - 1) = 7 + i
z₁ - z₂ = 5 + 2i - (2 - i) = 5 + 2i - 2 + i = 3 + 3i
z₁z₂ = (5 + 2i)(2 - i) = 10 - 5i + 4i - 2i² = 10 - i + 2 = 12 - i
z₁/z₂ = (5 + 2i)/(2 - i) = (5 + 2i)(2 + i)/(2 - i)(2 + i) = (10 + 5i + 4i + 2i²)/(4 - i²) =
= (10 + 9i - 2)/(4 + 1) = (8 + 9i)/5 = 1,6 + 1,8i
V1=1м^3
V2=0.29*0.15*0.8=0.0348м^3
m2/V2=m1/v1 => m1=m2v1/v2=281.88*1/0.0348=8100кг(ответ)
-24y²+1,4y-0,49=0
24y²-1,4y-0,49=0 1,4=7/5 0,49=49/100
D=(7/5)²+4*24*49/100)=49/25+24*49/25=25*49/25=49 √D=7
y1=(7/5+7)/(24*2)=(7+35)/(5*48)=42/(5*48)=7/(5*8)=7/40
y2=(7/5-7)/48=(7-35)/(5*48)=-28/(5*48)=-7/(5*12)=-7/60
ответ y1=7/40; y2= - 7/60