\(a,A=\dfrac{3}{7}-\dfrac{5}{2}-\left(-\dfrac{3}{7}\right)+\sqrt{\dfrac{1}{4}}-2022^0\\ =\dfrac{3}{7}-\dfrac{5}{2}+\dfrac{3}{7}+\dfrac{1}{2}-1\\ =\left(\dfrac{3}{7}+\dfrac{3}{7}\right)+\left(-\dfrac{5}{2}+\dfrac{1}{2}\right)-1\\ =\dfrac{6}{7}-2-1\\ =\dfrac{6}{7}-3\\=\dfrac{6-3\times7}{7}\\ =\dfrac{6-21}{7}=-\dfrac{15}{7}\)
\(b,B=\left(-0,125\right)^5.8^5+\left[\dfrac{16}{81}:\left(-\dfrac{4}{3}\right)^2+\dfrac{24^3}{12^3}\right]-1^{2021}\\ =\left(-0,125\times8\right)^5+\left[\dfrac{16}{81}:\dfrac{16}{9}+2^3\right]-1\\ =\left(-1\right)^5+\left(\dfrac{16}{81}\times\dfrac{9}{16}+2^3\right)-1\\ =-1+\left(\dfrac{1}{9}+8\right)-1\\ =-1+\left(\dfrac{1}{9}+\dfrac{72}{9}\right)-1=-2+\dfrac{73}{9}\\ =\dfrac{-2.9+73}{9}\\ =\dfrac{55}{9}\)