Respuesta :

9h - 12h = 54 - 23
-3h = 31
h = -31/3 or if u need it in mixed number form, it is - 10 1/3
Solutions  

Simplify 9h−12h to −3h

−3h = 54 − 23 

Simplify 54−23 to 31

−3h = 31

Divide both sides by −3 

= 31 / -3 

Simplify 31 / −3 to 31 / 3

h = −31 / 3