X^3 + 4*x^2 - 4*x -16 = x^2 * (x + 4) - 4 * (x - 4) = <span>(x + 4) * (x^2 - 4)</span>
4a^2-20a+25+20a-5a^2=-a^2+25
(-2/5)^2+25=4/25+25=25целых4/25
Задача 5
3.5*6.4*10⁻³=22,4*10⁻³=2,24*10⁻²
задача 6
(x⁻¹-y⁻¹)(x-y)⁻¹=
x⁻¹-y⁻¹=1/x-1/y=(y-x)/xy
· (x-y)⁻¹=1/(x-y)
= -1/xy