Find a common denominator.

$=\frac{5x}{15}-\frac{3(x+1)}{15}$

Simplify the fractions and combine like terms.

$=\frac{5x-3x-3}{15}$

$=\frac{2x-3}{15}$

See part (a).

$\frac{5x+3}{x^{2}}$

Reduce by the Giant One.

$=\frac{7}{1}\cdot\frac{x^{2}}{x^{2}}\cdot\frac{m}{m}$

Multiply by the reciprocal of $m^{2}$.