6. выражение: 1) корень 6 степени(х – 7)^6 при х > =7,x < 7; 2)корень 9 степени(3х + 8)^9 + конень 4 степени(х – 2)^4, при x < 2.​

1) x⁸+x⁴+1 = (x⁴)² + 2x⁴ +1² - x⁴ = (x⁴+1)²  - (x²)² = (x⁴+1-x²)(x⁴+1+x²) =
= (x⁴-x²+1)(x⁴+x²+1) = (x⁴-x²+1) ( (x²)² +2x²+1² - x² ) = 
= (x⁴ -x²+1) ( (x²+1)² - x² ) = (x⁴-x²+1)(x²+1-x )(x²+1+x)=
= (x⁴ -x²+1)(x²-x+1)(x²+x+1)

2) a³-3a+2 =  a³ - 1³  -3a+3 = (a-1)(a²+a+1) -3(a-1) = 
= (a-1)(a²+a+1-3) = (a-1)(a²+a-2)= (a-1)(a²+2a-a-2) =
= (a-1)(a(a+2) -1(a+2)) = (a-1)(a-1)(a+2) =
= (a-1)²(a+2)

3)x⁴+x²y²+y⁴= (x²)² + 2x²y² +(y²)² - (xy)²= 
= (x²+y²)² - (xy)² = (x² +y²- xy)(x²+y²+xy)

4)x³+3x²-4 = x³ +2x² + x² - 2² = x²(x+2) +(x+2)(x-2) =
=(x+2)(x² +x-2) = (x+2)(x² -1 +x-1) = (x+2)( (x-1)(x+1) +1(x-1)) =
= (x+2)(x-1)(x+1+1) = (x+2)²(x-1)

Y ' =( 2(x²-4)-x *2*2x)/(2x²-8)²= ( -2x²-8)/(2x²-8)²=- ( x²+4)/2(x²-4)²
y"=( 2x *2(x²-4)²-(x²+4)4(x²-4)2x )/4(x²-4)^4=(x(x²-4)-(x²+4)2x)/(x²-4)³=-x(x²+12)/(x²-4)³