А) 4y-1-2y+7+3y-1 5y+5 5(y+1)
--------------------- = -----------= --------- =
5y 5y 5y
y+1 y 1
----- = ----+ -----= y+1
y y y
л) 2×(a-b)×(a+b) 2a+6b 2×(a-b)
------------------- × -----------= ---------- =
2×(a+3b) b(a+b) b
2a-2b 2a 2b 2a
----------= ------ - ----- = ---- - b
b b b b
Y=
![\frac{3}{3x^2+x}](https://tex.z-dn.net/?f=+%5Cfrac%7B3%7D%7B3x%5E2%2Bx%7D++)
D(x):3x^2+x≠0
x(3x+1)≠0
x≠0 x≠-1/3
x∈(-∞;-1/3)∪(-1/3;0)∪(0;+∞)