1)х(4-у)
2)а^4(a^3+1)
3)12x^2(2^y+3y)
4)-4a(2b+3*2b+6^b)
5)x^2(x^2+6x+9x)
81^1/5 * 9^1/10 = 3^4/5 * 3^2/10 = 3^(4/5 + 1/5) = 3^1 = 3
(sina+sinb)^2+(cosa+cosb)^2=sina^2+2sina*sinb+sinb^2+cosa^2+2cosa*cosb+cosb^2=<span>=1+1+2sina*sinb+2cosa*cosb=2+2cos(a-b)=2(1+cos(a-b))</span>
∠1+∠2=180°
∠1=∠2+50° ⇒ ∠1+∠2=∠2+50°+∠2=2*∠2+50°=180°
2*∠2=180°-50° , 2*∠2=130° , ∠2=65°
∠1=65°+50°=115°
∠3=∠1=115° , ∠4=∠2=65°