Y= -x - 7/2. Y is equal to Negative X Minus 7 over 2.
Step-by-step explanation:
"she and her 2 sisters" means that there are in total 3 sisters, who share the stuff.
3 posters divided for 3 sisters gives every sister 1 poster.
7 would be the number cause;
25 ÷ 7 = 3 r4
hope that helps :D