\(B=\left(\dfrac{2\left(3-\sqrt{5}\right)}{9-5}+\dfrac{2-\sqrt{5}}{4-5}\right)\sqrt{\left(\sqrt{5}+1\right)^2}\\ B=\left(\dfrac{3-\sqrt{5}}{2}-\sqrt{5}+2\right)\left(\sqrt{5}+1\right)\\ B=\dfrac{\left(3-\sqrt{5}-2\sqrt{5}+4\right)\left(\sqrt{5}+1\right)}{2}\\ B=\dfrac{\left(7-3\sqrt{5}\right)\left(\sqrt{5}+1\right)}{2}=\dfrac{4\sqrt{5}-8}{2}\\ B=2\sqrt{5}-4\)