1) (a+b)/(15ab)*(30a²b)/((a+b)*(a-b)) - 1= (2a)/(a-b) - 1
при a=2 b = -2
(2*2)/(2+2) - 1=1-1=0
2) (4b(a-b))/(a(a³+1))*(a³+1)/(5(a-b))+20 = 4b/5a+20
при a=5 b= -4, (4*(-4))/(5*5)+20 = -16/25+20 = 19.36
3) ((1-9b)(1+9b))/((a-5)(a+5))*(a+5)/(9b+1)-1/(a-5) = (1-9b-1)/(a-5) = 9b/(5-a)
при a = 0 b= -2.5
(9*(-2.5))/(5-0) = -22.5/5= -4.5
4) (6a²(b-1))/(b+2)*(5(b+2))/(12a³)+5/(2a) = (b-1)/(2a)+5/(2a) = (b+4)/(2a)
при a=10 b=11,
(11+4)/(2*10) = 15/20 = 3/4 = 0.75