1. a) (5–6a)/3a–(1–2b)/b=(5b–6ab–3a+6ab)/3ab=(5b–3a)/3ab
б) 12х^2/(5х–10)•(х–2)/18х =
= 12х^2*(х–2)/90х(х–2) = 6х/45
в) (а–b):(a–b)(a+b)/3a^2=3a^2/(a+b)
2. 14n/(n–3)+12n/(3–n)^2•5(3–n)/4=
= -14n/(3–n)+12n*5(3–n)/4(3–n)^2=
= -14n/(3–n)+15n/(3–n)=
= (-14n+15n)/(3–n)=n/(3–n)
3. (x/(x–y)+2xy/(x–y)^2)•(2x/(x+y)–1) =
=(x(x–y)+2xy)/(x–y)^2)•(2x–x–y)/(x+y)
=(x^2–xy+2xy)/(x–y)^2)•(x–y)/(x+y) =
=x(x+y)(x–y)/(x–y)^2(x+y)=x/(x–y) =
= -2/(-2+1)=2
4. (x+2)^2/2 – (x^2–4)/4 – (x–2)^2/8 = x^2/8
(4(x+2)^2–2x^2+8–(x–2)^2)/8=x^2/8
4x^2+16x+16–2x^2+8–x^2+4x–4–x^2=0
20x=–20
x=–1