Question

Упростите выражение и найдите его значение при
у = 1,5.
(2y-1)(4y^2+2y+1)-y(y-1)(y+1)​

Answer 1

$y=1.5\\\\(2y-1)(4y^2+2y+1)-y(y-1)(y+1) = 8y^3-1-y(y^2-1) = \\= 8y^3-1-y^3+y = 7y^3+y-1 = 7*(1.5)^2+1.5-1 = 16.25\\\\ \boxed {(a-b)(a^2+ab+b^2)=a^3-b^3; \: (a-b)(a+b)=a^2-b^2}$