Respuesta :
[tex]\huge\text{Hey there!}[/tex]
[tex]\large\boxed{\mathsf{a + b}}\\\large\boxed{\mathsf{= -15.4 + -13.5}}\\\large\boxed{\mathsf{= -15.4 + (-13.5)}}\\\large\boxed{\mathsf{= -15.4 - 13.5}}\\\large\boxed{\mathsf{= -28.90}}\\\large\boxed{\mathsf{= -28.9}}\\\\\large\boxed{\mathsf{Therefore, your\ answer\ is: -28.9}}\large\checkmark[/tex]
[tex]\huge\text{Good luck on your assignment \& enjoy your day!}[/tex]