Given that sqrt 128 sqrt 18 - sqrt k find K - WAEC Mathematics 2004 Question

(\sqrt{128} +\sqrt{18}-\sqrt{k}=7\sqrt{2}<br /> \sqrt{2\times 64}+\sqrt{9\times 2} - \sqrt{k} = 7\sqrt{2}<br /> 8\sqrt{2} + 3\sqrt{2} - \sqrt{k} = 7\sqrt{2}; 11\sqrt{2} - \sqrt{k} = 7\sqrt{2}<br /> -\sqrt{k}=7\sqrt{2}-11\sqrt{2}; -\sqrt{k} = -4\sqrt{2}; \sqrt{k}=4\sqrt{2}<br /> =\sqrt{4^2\times 2} = \sqrt{16\times 2}; \sqrt{k}=\sqrt{32}; k = 32)