$\dfrac{4}{7}\left(\dfrac{21}{8}x+\dfrac{1}{2}\right)=-2\left(\dfrac{1}{7}-\dfrac{5}{28}x\right)\\\\\text{use the distributive property}\ a(b\pm c)=ab\pm ac\\\\\left(\dfrac{4}{7}\right)\left(\dfrac{21}{8}x\right)+\left(\dfrac{4}{7}\right)\left(\dfrac{1}{2}\right)=(-2)\left(\dfrac{1}{7}\right)-(-2)\left(\dfrac{5}{28}x\right)\\\\\dfrac{4\cdot21}{7\cdot8}x+\dfrac{4\cdot1}{7\cdot2}=-\dfrac{2}{7}+\dfrac{2\cdot5}{28}x\qquad\text{simplify}$

$\dfrac{3}{2}x+\dfrac{2}{7}=-\dfrac{2}{7}+\dfrac{5}{14}x\qquad\text{multiply both sides by 14}\\\\(14)\left(\dfrac{3}{2}x\right)+(14)\left(\dfrac{2}{7}\right)=(14)\left(-\dfrac{2}{7}\right)+(14)\left(\dfrac{5}{14}x\right)\qquad\text{simplify}\\\\(7)(3x)+(2)(2)=(2)(-2)+(1)(5x)\\\\21x+4=-4+5x\qquad\text{subtract 4 from both sides}\\\\21x+4-4=-4-4+5x\\\\21x=-8+5x\qquad\text{subtract}\ 5x\ \text{from both sides}\\\\21x-5x=-8+5x-5x\\\\16x=-8\qquad\text{divide both sides by 16}$