Step-by-step explanation:
1.
[tex] \frac{15}{12} = \frac{15 \div 3}{12 \div 3} = \frac{5}{4} [/tex]
2.
[tex] - \frac{12}{15} = - \frac{4}{5} [/tex]
3.
[tex] \frac{12}{15} = \frac{4}{5} [/tex]
4.
[tex] - \frac{15}{12} = - \frac{5}{4} [/tex]
