10^15*10^7/10^19=10^22/10^19=10^3=1000
7^8/7*7^7=7^8/7^8=1
(-3)^5*(-3)^3/(-3)^7=(-3)^8/(-3)^7=-3
(0.2)^8*(0.2)^2/(0.2)^4*(0.2)^3=(0.2)^10/(0.2)^7=(0.2)^3=0.008
1) SIn2x = 2SinxCosx
Sin2x = √2Cosx
2SinxCosx - √2Cosx = 0
Cosx(2Sinx - √2) = 0
Cos x = 0 или Sinx = √2/2
x₁ = π/2 + πk, k∈Z
2) 2SinxCosx + √2Sinx = 0
Sinx(2Cosx + √2) = 0
Sinx = 0 или Cosx = -√2/2
x₁ = πk
x₂ = ±3π/4 + 2πk
Ответ:
a)ab-7c = 8×(-3)-7×(-1/7)=-24+7/7=-24+1=-23
б)ab+cb+c=1/7×14 + (-2)×14+(-2)=2-28-2=-28
A²-10ab+25b²=(a-5b)²
25+10x+x²=(5+x)²
k⁴+2k²+1=(k²+1)²
p²-1,6p+0,64=(p-0,8)²