The thickness of an 800 pages of book is 18mm. Calculate the thickness of one leaf of the book giving your answer in meters and in standard form

Simplify \(\frac{4a^2 - 49b^2}{2a^2 - 5ab - 7b^2}\)

If \(\cos^2 \theta + \frac{1}{8} = \sin^2 \theta\), find \(\tan \theta\).

Simplify \(\frac{x^2 - y^2}{2x^2 + xy - y^2}\)

Solve the following equation \(\frac{2}{2r - 1}\) - \(\frac{5}{3}\) = \(\frac{1}{r + 2}\)