$(a)\;\bigg[(\frac{2y+3}{2x+1}-1)^2-2 \bigg] c^2 \bigg(\frac{2x+1}{2}\bigg)^2=1 \\ (b)\;\bigg[(\frac{2x+1}{2y+3}-1)^2-2 \bigg] c^2 \bigg(\frac{2x+1}{2}\bigg)^2=1 \\ (c)\;\bigg[(\frac{x+1}{y+3}-1)^2-2 \bigg] c^2 \bigg(\frac{2x+1}{2}\bigg)^2=1 \\ (d)\;\bigg[(\frac{y+3}{x+1}-1)^2-2 \bigg] c^2 \bigg(\frac{2x+1}{2}\bigg)^2=1 $