$(1)$计算：$\sqrt[\begin{smallmatrix}3\\\end{smallmatrix}]{\dfrac{1}{8}}+{{(-1)}^{2000}}+\sqrt{\dfrac{1}{4}}-|-5|.$

$(2)$解方程组；$\left\{\begin{array}{l}2x+y=1.5\\ 0.8x+0.6y=1.3\\\end{array}\right.$

$(3)$解不等式组$\left\{\begin{array}{l}2-x>0\\ \dfrac{5x+1}{2}+1\geqslant\dfrac{2x-1}{3}\\\end{array}\right.$，并把解集在数轴上表示出来．