10c-5a=5(2с-а)
14a-42b+196=14(а-3b+14)
bx-x=x(b-1)
2xy-12xz=2x(y-6z)
d³x-b²xy=x(d³-b²y)
2x²y³-6x³y²+10xy²=2xy²(xy-3x²+5)
a²b-3ab²+4a³b²=ab(a-3b+4a²b)
<span>определите ctg t, если t=7п/4</span><span> Ответ: ctg 7п/4= ctg 315 градусов= -1</span>
B₁ + b₁ q + b₁ q² = 78/125
b₁ (1 + q + q² )= 78/125 |q| < 1
S = b₁/(1-q)
b₁ = S/(1 - q) = 2/3(1 - q)
2/3(1-q)(1+q+q²) = 78/125
1 - q³ = 78/125 : 2/3
1 - q³ = 117/125
q³ = 1 - 117/125 = 8/125
q = ∛8/125 = 2/5
b₁ = S * (1 - q) = 2/3 * (1 - 2/5) = 2/3 * 3/5 = 2/5 = 0,4