X 2 -3 5
Y 5.4 4.4 6
Просто по этим токам построй и все
0.3:(1+1/9)=0.3:10/9=0.27
1) 0,04a^2-2ay+25y^2
2)0,09x^2+2,4xy+16y^2
3) 1,69m^2+6,5mn+6,25n^2
4) 1 2/3? Или что? Непонятно
Делаешь так, пример:
(Х+у)^2=х(Х+у)+у(Х+у)=х^2+ху+ху+у^2= х^2+2ху+у^2
г)
b₁ + b₂ + b₃ = 7
b₁b₂b₃ = 8
bₙ = b₁ qⁿ⁻¹
b₁ * b₁q * b₁q² = b₁³ q³ = 8
b₁q = 2
b₁ + b₁q + b₁q² = b₁ + b₁q + b₁q*q = b₁ + 2 + 2q = 7
b₁ + 2q = 5
b₁ = 5 - 2q
(5 - 2q)q = 2
2q² - 5q + 2 = 0
D = 25 - 16 = 9
q₁₂ = (5 +- 3)/4 = 2 и 1/2
1. q = 2 b₁ = 5 - 2q = 5 - 4 = 1
2. q = 1/2 b₁ = 5 - 1 = 4
б)
b₂ = 10
b₃ + b₄ = 60
b₃ = b₂q
b₄ = b₃q = b₂q*q = b₂q²
b₂q + b₂q² = 10(q + q²) = 60
q² + q - 6 = 0
D = 1 + 24 = 25
q₁₂ = (-1 +- 5)/2 = 2 и -3
1. q = 2 b₂ = b₁q = 2b₁ = 10 b₁ = 5
2. q=-3 b₂ = b₁q = -3b₁ = 10 b₁ = - 10/3