Express \(\log _ { 3 } ( 4 x + 7 ) - \log _ { 3 } x\) as a single logarithm.
Hence solve the equation \(\log _ { 3 } ( 4 x + 7 ) - \log _ { 3 } x = 2\).
Use the trapezium rule, with two strips of width 3, to find an approximate value for
$$\int _ { 3 } ^ { 9 } \log _ { 10 } x \mathrm {~d} x ,$$
giving your answer correct to 3 significant figures.