1. (5 25/100-4 21/40):1,45-(7 1/3-6,875):0,75=(5 10/40-4 21/40):1,45-(7 1/3-6 7/8):0,75= (40/40+10/40-21/40):1,45-(24/24+8/24-21/24):0,75=29/40:145/100-11/24:75/100=29/40*100/145-11/24*100*75=1/2-11/18=(9-11)/18=-2/18=-1/9
2. ((x^2+4)/(x-2)^2)+((2-x)(x-2))*(x/(x^2-4))=(((x^2+4+(2-x)(x+2))/(x-2)^2)*((x^2-4)x)=((x^2+4+4-x^2)/(x-2)^2)*((x-2)(x+2)/x)=(8(x+2))(x(x-2))