Hi,
Solving:

Answer: y = -128
Hope this helps.
If you have any questions about the answer, comment below and I'll reply.
r3t40
Answer:
d is the right answer for your question
Let a and b be store A and store B, respectively. Then:
3a+b=63
5a+4b=140
So
12a+4b=252
5a+4b=140
7a=112
a=16
b=15
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