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
4. z^2+1-z^2-2z-1=-2z
5. x^2-4x+4+x^2+7x-5x-35=2x^2-2x+4=2(x^2-x+2)
6. 3(a^2-2a+1)+8a=3a^2-6a+3+8a=3x^2+2a+3
7. y^2+2xy-x^2-2xy-y^2=-x^2
8. b^2+8b+16-b^2+6b-9=14b+7=7(2b+1)