Find the roots of the following quadratic equation by the method of completing the square: $m^{2}-18m+81=0$

Find the roots of the following quadratic equation by factorisation:
$x^{2}-3x-10=0$

The altitude of a right triangle is $7 \, cm$ less than its base. If the hypotenuse is $13 \, cm$,find the other two sides.

An express train takes $1\, hour$ less than a passenger train to travel $132\, km$ between Mysore and Bangalore (without taking into consideration the time they stop at intermediate stations). If the average speed of the express train is $11\, km/h$ more than that of the passenger train,find the average speed of the two trains. (in $km/h$)

Solve the following equation using the method of factorization and write its solution set: $\frac{1}{x-2}+\frac{1}{x+3}=\frac{7}{2x}$ $(x \neq 2, x \neq -3, x \neq 0)$

Solve the following equation using the method of factorization and write its solution set: $4x^{2} + 4x = 15$.