Answer:
One used book cost 5$ and a new book cost 15$
Step-by-step explanation:
lets multiply the second equation ×(-2)
×
if u = 5 then from equation 1
12*u + 4n = 120, 60 +4n = 120, 4n=120-60, n=60/4, n=15
Answer: u=$5, n=$15 APEX
no thanks but I'll see if I can get friends to join
hope its help brain least me
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That is exactly the hardest problem to solve in history!
hope i helped