<span>(2х-1)(15+9х)-6х(3х-5)=87
30x+18x^2-15-9x-18x^2+30x=87
</span>30x-15-9x+30x=87
51x=102
x=2
а) 16х^4-81y^4=(4x^2-9y^2)(4x^2+9y^2)=(2x-3y)(2x+3y)(4x^2+9y^2)
б)48a^4-3b^4=3(4a^2-b^2)(4a^2+b^2)=3(2a-b)(2a+b)((4a^2+b^2)
в)1/81m^8-1=(1/9m^4-1)(1/9m^4+1)=(1/3m^2-1)(1/3m^2+1)((1/9m^4+1=(1/V3 m-1)(1/V3 m+1)(1/3m^2+1)((1/9m^4+1)
г)32-1\2 m^6=1/2(64-m^6)=1/2(8-m^3)(8+m^3)=1/2(2-m)(4+2m+m^2)(2+m)(4-2m+m^2)
3k, 5k, 7k
где k - любое натуральное число.