Answer:
-9t
Step-by-step explanation:
(r-s) 3 × t × r
(-3- -4) 3 × t × -3
3 × t × -3
A.Neither they pay the same .
a=13
b=5
c=16.25
d=26.25
A u B = {3,5,6,7,8,11,12}
A = {3,6,7,11}
B = {3,5,7,8,12}
ok
+ 
or x = - + -