hope this helps! let me know if i am wrong!
F(x) = x^2 + 4x - 5
[f(a + h) - f(a)] / h
f(a) = a^2 + 4a - 5
f(a + h) = (a + h)^2 +4(a + h) - 5
= a^2 + 2ah + h^2 + 4a + 4h - 5
f(a + h) - f(a) = a^2 + 2ah + h^2 + 4a + 4h - 5 - ( a^2 + 4a - 5)
---------------- ------------------------------------------------------------
h h
= 2ah + h^2 + 4h h (2a + h + 4) 2a + h + 4
------------------- = ------------------- =
h h
Amount left in account after paying for music class = $87.60 - $25.60 = $62
Amount in the bank account after 10 months = $62 x 10 = $620
Amount spent to go to the summer camp = 1/4 x $620 = $155
Answer:
56 because you have to multiply 28 times 2
