1) 2y(6x +¹/₄y)² - x(8x+3y)² =
=2y(36x² +3xy+¹/₁₆ y²) - x(64x²+48xy+9y²)=
=72x²y+6xy² +¹/₈ y³ - 64x³ -48x²y -9xy²=
=¹/₈ y³ - 3xy² +24x²y -64x³ =
=(¹/₂ y)³ - 3*(¹/₂ y)² *4x + 3* ¹/₂ y *(4x)² - (4x)³ =
<span>=(¹/₂ y -4x)³</span>
(-3.9х2.8+26.6):(-3.2)-2.1=(-10.92+26.6):(-3.2)-2.1=15.68:(-3.2)-2.1=-4.9-2.1=-7
<span>(y^4-x^4)/(x^3-y^3)=(x^2-y^2)*(x^2+y^2)/((x-y)(x^2+xy+y^2))=</span>
=(x-y)*(x+y)*(x^2+y^2)/((x-y)(x^2+xy+y^2))=
=(x+y)*(x^2+y^2)/(x^2+xy+y^2)
Ответ:
Объяснение:
1) =1-10y+25y^2+15y-25y^2=1+5y
1+5 (-1,8)=1-9=-8
2) 4x-15x+10=5-x-6
-11x+10=-1-x
-10x=-11
X=1,1
po formule cos2x=cos^2x-sin^2x