243/10:(-174/10)-214/10=243/10×(-10/175)-214/10=243/175-214/10=243/175-107/5=243-3745/175=-3502/175=-20 целых 2/175
<span>3*k-81*k^4=3*k*(1-27*k^3)=</span>
<span>3*k*(1-3*k)*(1+9*k+9*k^2)</span>
<span>a^5*b-a^3*b^3-a^2*b^4+b^6=</span>
<span>a^2*b(a^3-b^3)-b^3*(a^3-b^3)=</span>
<span>b*(a^2-b^2)*(a^3-b^3)=</span>
<span>b*(a+b)*(a-b)^2*(a^2+a*b+b^2)</span>
=(a-5)²-2(a-5)+1=(a-5)(a-5-2)+1=(a-5)(a-7)+1
Tgx = 2
x = arctg 2 + pik, k ∈ Z