There is no attachment to your phone question. I look forward to answer your question.
Amy would have spent $22.5 on her books (assuming you meant $10 total, not $10 per book)
We know that if we had
8/6=2/2 times 4/3=1 times 4/3=4/3
find common factors in top and obttom
factor
48a^4-16a^2-32=(16)(a-1)(a+1)(3a^2+2)
8a^2-8=8(a-1)(a+1)
so we have
(2)(3a^2+2)=6a^2+4
answer is 6a^2+4