Given that k k\,k is an integer, express 18−k4−8\displaystyle \frac{\sqrt{18}-k}{4-\sqrt{8}}4−818−k in the form a+b2a+b\sqrt{2}a+b2 where a a\,a and b b\,b are rational expressions in terms of kkk.
134 exam-style questions on Edexcel AS Level Maths Algebraic Expressions, covering 1.1 Index Laws, 1.2 Expanding Brackets, 1.3 Factorising, 1.4 Negative and Fractional Indices, and 1.5 Surds. Each one has a worked solution and a mark scheme showing where the marks go.