Express each of the following rational numbers in its standard form:
(i) \(\dfrac{-12}{-30}\)
(ii) \(\dfrac{14}{-49}\)
(iii) \(\dfrac{-15}{35}\)
(iv) \(\dfrac{299}{-161}\)
(i) \(\dfrac{2}{5}\)
(ii) \(-\dfrac{2}{7}\)
(iii) \(-\dfrac{3}{7}\)
(iv) \(-\dfrac{13}{7}\)
Simplify and make denominator positive to get standard form.