Respuesta :

TSO
r + s + t

Plug in the values.
r = 26
s = -12
t = -8

r + s + t
26 + (-12) + (-8)
26 - 12 - 8
14 - 8
6

Remember these rules:

a + (+b) = a + b
a + (-b) = a - b
a - (+b) = a - b
a - (-b) = a + b