$a.\sqrt{x+1}+\sqrt{3-x}=\sqrt[4]{2}.(\sqrt[4]{x+1}+\sqrt[4]{3-x})$
$b.64x^{6}-112x^{4}+56x^{2}-7=2\sqrt{1-x^{2}}$
$d. \sqrt[4]{14x+2}+\sqrt[4]{6x+1}=\sqrt[4]{x}$
$\frac{1}{x^{2}+5x+4}+\frac{1}{x^{2}+11x+28}+\frac{1}{x^{2}+23x+130}+\frac{1}{x^{2}+17x+70}=\frac{4}{13}$