(a)110\(_x\) - 4\(0_5\) 1 x \(x^2}\) + 1 x \(x^1\) + 0 x \(x^o\) x = 4 x 5\(^1\) + 0 x 5\(^o\) x\(^2\) + x = 4 x 5 + 0 x\(^2\) + x - 20 = 0 (x - 4)(x + 5) = 0 x - 4 = 0 or x + 5 = 0 x = 4 or x = -5 x = 4 (b) Simplify \(\frac{15}{\sqrt{75}}\) + \(\sqrt{108}\) + \(\sqrt{432}\) = \(\frac{15}{\sqrt{25 \times 3}}\) + \(\sqrt{36 \times 3}\) = \(\frac{15}{5 \sqrt{3}\) + 6\(\sqrt{3}\) + 12\(\sqrt{3}\) = \(\frac{15 \sqrt{3}}{15 \times \sqrt{3} \times \sqrt{3}}\) + 18\(\sqrt{3}\) = \(\frac{15\sqrt{3}}{15}\) + 18\(\sqrt{3}\) \(\sqrt{3}\) + 18\(\sqrt{3}\) = 19\(\sqrt{3}\)